DATE PRODUCTS AND PREPARATIONS
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Dates are ambiguous in the sense that, depending on the stage of maturity, they can either be classified as a fruit, comparable to any other fruit consumed between meals, or alternatively, as a food source as part of the daily meal, in particular in the rural areas of the date producing countries. Though not a true staple food by definition like rice, potatoes or cassava, dates, on occasion, have been forced to play this role for lack of other staples. In recent times, either because of a decreasing demand for table dates or in an effort to make better use of off-grade fruit, there has been a renewed interest in the date as a food source, not necessarily as a staple food, but rather as a component in food preparations like sweets, confectionery, baking products, institutional feeding and health foods.
In this Chapter a review is made of the use or potential use of dates in combination with other foodstuffs. Only the use of the whole date flesh is considered and therefore all quality standards as imposed on whole dates, except perhaps for blemishes and other external defects, are applicable. In Chapter III: "Derived Date Fruit Products" the use of dates will be extended to a group of products for which the initial quality demands, in particular with regard to foreign matter and insects, are less stringent, because the foreign matter can be effectively removed during processing and will have no effect on the quality of the derived product.
Although demarcations are not always sharp, date products and preparations, based on the use of the whole date flesh, can be classified under: sweets, preserves, condiments, breakfast foods and desserts . In order to follow somewhat the historical developments in this field they are reviewed as home preparations, semi-finished products, and ready-for-use date products after which research work on new date products will be listed.
2.1 Home-made date preparations
Include those dishes and foods for which whole dates are acquired by the housewife and incorporated or combined for home consumption. Preparation of the dates, according to the intended use, will normally consist of washing, hand pitting, and either cutting, slicing or mixing with water to prepare a date slurry.
Literature, both old and more recent, is abound with references to dates being consumed in food combinations and - preparations. The date's organoleptical and nutrititional characteristics being what they are, that is rich in sugar, and low in protein and fat, it stands to reason that a large number of combinations are focussed on supplementing the nutritional shortcomings and perhaps also diluting the natural sweetness of dates and sometimes adding some acidity, which they lack. Fresh dates are therefore often found in combination with milk (fresh and sour) and milk products, such as yoghurt, curd, butter and cheese. Dates are also stewed in fresh milk or thoroughly mixed with milk powder (513). A refined delicacy consists of dates, butter and honey, named Khabis, and reportedly known from the time of Mohammed, the Prophet (445). Extending the date and protein combination, one comes across dates and fish which has been a long-standing staple in the Gulf area (445), which, incidentally, finds a reciprocal appreciation for dates by fish, because in ancient Egypt dates were used as fish bait (127). Although perhaps a strange combination to a Western palate it should not be rejected off-hand if one thinks of the recipes in the West based on a sweet with animal protein like apple sauce or prunes and pork, cranberry sauce with turkey, which in Naples finds a parallel in turkey prepared with a stuffing incorporating dates. But this tolerance for accepting unusual food combinations would probably stop for most people when being confronted with dates mixed with oil and boiled, dried and ground locusts which apparently was considered a delicacy in those countries where these insects are abundant from time to time (445). Ground dates mixed with sesame oil is a well known dish and probably most effective with which to pass the cold desert nights.
A typical example of complementarity in the consumption of fruits and vegetables is the combination of dates and either cucumbers or water melons, in which the sweetness of the date is diluted and the taste of the cucumber or water melon is reinforced. In more recent times these combinations are extended to recipes for date fruit salads, using pineapple, citrus, apples, pears, celery and lettuces.
Date and starch preparations are frequently found and normally need cooking or frying. Examples are dates stewed in fresh milk with onions and flour or a stew of dates and rice in milk commonly used for lactating mothers (445). Adding sesame paste (tehina) to cooked flour and dates adds extra flavour to a product called Tamreyya (513) especially used in winter and by women after childbirth.
Honeiny consists of comminuted dates thoroughly mixed with a precooked thick dough and reheated on a flat plate and served with butter (512). A common, traditional dish based on dates and flour, found in many date producing countries but with many variations is Asseeda. A traditional Asseeda from East Saudi Arabia (512) would be made by roasting wheat flour briefly (1,000 g.) and adding it to a coarsely sieved date/water mixture (2,350 g., 11.5° Bx). After mixing thoroughly and adding some pepper (3 g.) the mixture is spread on a flat metal plate with a small amount of butter and cooked in the oven for 1.5 hours. Asseeda is served with some more butter (40 g.) (512). However, there are many variations of this recipe: other flours may be used (sorghum, millet), date syrup or molasses may replace dates, and other spices, e.g. cardamom can be added.
Dates are frequently used in home made pastry. A typical date sweet (halwa tamr) is made by frying finely ground dates with flour and milk and forming this mixture into cakes (445). Another date sweet consumed on festive occasions in and around Mecca is Debiaza, made by concentrating date juice, to which dates, dried lemon and mint are added, until it gels (512).
Dates and nuts (walnut, pistachio, almonds), and also sesame seed, are a well-appreciated combination and frequently prepared in different forms for home use. Nuts also often play a role in preparing home preserves as shown from the following example: peel hard dates with a knife, cover with water and boil until soft, remove seed and insert almond or pistachio nuts and a clove, boil dates in syrup with lemon until thick consistency, preserve in glass or glazed jars (445).
Another more or less similar recipe adds, besides walnuts, sesame seeds and powdered ginger before pressing and storing the mixture under syrup in glass jars. Home made jams based on dates are also known, as the following example from Egypt shows: cook semi-dry dates in water to soften, remove skin and seed, and insert a clove, add half a cup of sugar to one cup of dates, add lemon juice and original cooking water, concentrate over low fire. Leaving out the lemon juice and clove and replacing them with chopped walnuts gives another type of date jam (122).
It is clear that this list of home made date preparations in the traditional date producing countries is far from complete because so many variations are possible depending on local availability of other foodstuffs and prevailing traditions and customs.
The situation in the countries without local (traditional) production of dates is understandably different. In Europe the date is mostly used as a table fruit and then only mainly before and during the Christmas season, when lower temperatures and perhaps connotations of the date with the Holy Land, work in favour of an increased consumption of whole date fruit. Home made date preparations are more difficult to find; however the more inventive housewife may mix some chopped up dates in mixed salad, or fill up the dates with cheese as a cocktail snack (183), or stuff them with nuts for an after-dinner sweet.
Dates used in cooked foods are even more rare as witnessed by the paucity of recipes to this effect in the European cook books. However, a few interesting examples are given: (i) dates used in stuffing for chicken and turkey. A first version combines dates in pieces with pine seeds, minced meat, breadcrumbs, eggs, milk and spices; a second type uses dates, potatoes, eggs, cheese, raisins and nutmeg (181). The chicken or turkey meat can be further garnished with a sauce, prepared from dates in butter, orange juice and some brandy. (ii) dates with rice. Date pieces are lightly fried in butter, combined with slices of chicken breast. This mixture is combined with rice cooked in broth with cloves. (iii) date and fish. Sole or bass with some butter and herbs (thyme, rosemary) together with dates rolled in a slice of bacon, are wrapped together in aluminium foil and cooked in the oven (296). (iv) dates and pasta: ravioli pasta is stuffed with date pieces (mixed with nuts, if desired), deep fried and rolled in sugar (181). (v) date mousse. Dates and nut pieces are mixed with yoghurt to which egg yolk and cinnamon are added. The white of the egg is whipped separately with sugar until foamy and incor-porated with the yoghurt mixture to form a light, tasty dessert (182).
In the U.S., which only during this century became a date producer in its own right, strong and persistent promotional campaigns have made the housewife much more date-minded than in Europe, reflecting itself in a variety of date uses including cooked foods.
The emphasis on the use of date products prepared in the home is on baked products like bread, cakes, cookies and puddings either incorporated in the dough or as a filling. Dates are often used in combination with other dried fruit, especially apricots, raisins and figs. Also very popular are the admixtures with nuts, coconut, chocolate and sometimes ginger and vanilla.
For more contrasting tastes the following suggestions are made by a U.S. date grower/packer (291):
a) for sandwich spreads
i. chopped dates and cream cheese,
ii. chopped dates, peanut butter, salad dressing in equal amounts, mixed lightly with some lemon juice,
iii. chopped dates with orange marmalade
b) for party snacks
i. dates, stuffed with cocktail sausage, oven baked and served
on cocktail sticks,
ii. dates, stuffed with olives, rolled in thin cream cheese and chopped nuts,
iii. dates, stuffed with fondant, nutmeat or candied fruit,
iv. date chews, consisting of a mixture of ground dates, chopped nuts, shredded coconut, cream, vanilla, made into balls coated with sugar
c) for salads
i. chopped dates with grapes, peanuts, cottage cheese, bananas,
or celery and nutmeats,
ii. dates stuffed with Philadelphia cheese on pineapple slice served on lettuce
A recipe for a home-made date relish (134) combines chopped, pitted dates with sugar and ground raisins, spiced with garlic, ginger, red pepper, vinegar and a little salt. The mixture is boiled for 15 minutes and used as a sweet-sour condiment.
In order to promote the use of dates in home cooking the housewife is greatly helped by a number of semi-finished and prepared date mixtures available on the market and which will be reviewed in the next paragraph.
2.2 Semi-finished Date Products and Mixtures
The base material for the further industrial use of dates in mixtures and preparations are pitted dates, most of which are produced in macerators as described in Chapter I: "pitting", although for special purposes whole pitted, cut or sliced dates are also procured.
Out of this base material the following product range is available as semi-finished products:
a. macerated chips in 50 lb cases , usually going to bakers and confectioners who further convert it into the form desired by them. The product generally needs refrigeration because of the borderline moisture content for fermentation at which the date macerators operate most efficiently.
b. date paste: a simple additional grinding operation will turn the macerated date into date paste. The principle is the same as for prepared minced meat and the fineness of the product can be regulated by the use of different size holes in the discs. Here also, refrigeration may be required to prevent possible fermentation. Date paste is also produced commercially in Saudi Arabia and used for bakery products. The estimated volume of this product is 1,000 tons in this country. A curious non-food application of date paste is that it will, in combination with soap, efficiently stop leaks in gasoline tanks in automobiles (363). This will not open up large markets for date paste, but it may become a life saver on long desert journeys.
c. extruded date pieces: macerated dates are forced through dies with ¼" circular holes and the resulting "sausage" is cut at lengths varying from ½" to 1" whilst being coated with dextrose (solid glucose) or oat flour to prevent the pieces from sticking together. This product is sometimes air dried for more firmness or customer preference.
d. diced dates: a variant of above are diced dates which are cut up rather than extruded macerated dates. The operation is performed in a dicer, which can be set to produce pieces of about 3/16" to ½". They are also coated with dextrose or oat flour to keep the pieces separate.
e. dehydrated dates: macerated dates are put on trays and dried down to less than 5% moisture in tunnel or cabinet dryers. The dried dates are ground and sold in various screen sizes. The product is used in prepared cake-, cookie- and muffin mixes.
Some of the products are also sold directly to the public such as "extruded date pieces", "diced dates" and a "date block", which is a slightly pressed cube of macerated dates (10 oz or 1 lb size) for home baking.
A product under the name of Date Crystals, dehydrated fine date pieces, almost a powder, was put on the market and proposed as the basic ingredient in date recipes and taking the place of dates (526, 609) (Fig. 64). Another semi-finished product in the form of a spread, consisting of ground dates and sugar, was marketed as a base ingredient for the preparations of mainly cakes and desserts aimed as a raw material in the catering industry (434).
Figure 64: Dehydrated Dates in Powder Form
A second generation of semi-finished date products mainly developed in the U.S. are the prepared foods which with simple additions and home preparation can be turned into a ready dish. In this group belong the breakfast foods in which date crumbs are normally used together with other dried fruits, cereals and nuts (Fig. 65) and the ready mixtures for date bread (Fig. 66), date cakes and date puddings in their various executions. A specific example is the date bar mix (Fig. 67) which needs only the addition of water, eggs, baking powder and other optionals (e.g. walnuts, grated lemon rind, instant coffee, coconut) and oven cooking for 30 minutes to produce date bars (171).
2.3 Ready for Use Date Products
Ready for use date products incorporating dates are mostly found as sweets and snacks though there are also some other examples where dates are product ingredients.
In countries where taste for sweets, the so-called "sweet tooth", is still prevalent, notably in the date producing countries of the Old World, a great variety of coated and stuffed dates as well as pastry based on or garnished with dates, is available.
Dates filled with nuts and coated with chocolate or stuffed with brightly coloured fondant are only a few of the many date based sweets. Date pastry like halwa or date cookies (a sister of the Wellington or fig bar) and date wafers can be found in many countries (Fig. 68). In the U.S., and to a lesser extent in Europe, the popularity of dates especially in the Christmas season, has given rise to a gift parcel trade. It includes attractively packaged and arranged dates and date products which are, on order by the customer, sent by the producer as gift parcels through the postal system. The date products may consist of stuffed and coated dates, date cake with walnuts, date/plum pudding, date preserve and dates in brandy.
Figure 68: Several Types of Date Cookies
A popular sweet as a snack is the date nut roll. It is a cylindrical bar of about 3/4" and up to 2" in length of macerated dates, rolled in coconut and with an almond on top. A date-muesli bar (Fig. 69) consisting of hazelnuts, date syrup, dates, oatflakes, and sunflower seeds, is another example of a one-portion snack. Another product, also under the name of date nut roll is a canned ready date cake (based on dates, nut meats, coconut, flour and other minor ingredients), to be heated "au bain marie" and served after slicing with either sweet or spicy toppings (382). Less sweet and in analogy with the early desert travellers carrying dates along as a concentrated, high energy food, are the so-called trail snacks, mixtures of dried fruits including date pieces and nuts taken along on mountain hikes especially by younger people (Fig. 70).
Figure 69: Date-muesli Bar
Figure 70: Dried Fruit and Nuts Mixtures including
Date jams in different forms or admixed with other fruits are part of the product assortment of a few internationally oriented conserve industries (Fig. 71).
In conclusion of the ready date products available on the market mention should be made of several condiments, mixtures of sweet, sour and spices: date chutney (Fig. 72), steak sauce and pickles. In date chutney all or part of the mango (for which chutney as a product is better known) is replaced by dates, and mainly used as a condiment in rice dishes. Steak sauce (better known as HP sauce after the company that makes it) is a very old product, and is used as a condiment in meat dishes. It contains about 10% finely ground, sieved dates. A more fruity version is used as a general condiment (Fig. 73).
A product in between chutney and steak sauce is a pickle incorporating dates known under the name of Branston (named after the town where it was first created). Besides dates the different versions contain vegetables (pieces), fruits and spices. Its pleasant sweet-sour taste makes it an appropriate accompaniment to salads, cheese and cold meats (Fig. 74). A sweet type of pickle is shown in Figure 75.
Figure 74: Different Types of Pickle incorporating Dates
Figure 75: English Sweet Pickle
2.4 Date Products Development
The development of new products derived from dates to create more product diversity and marketing outlets has always existed and principally originated from small scale private initiatives of a localized nature. However, in the fifties and early sixties a strongly increased interest in date products development can however be observed, especially in the U.S., the reason being to broaden the marketing base of the date crop and upgrading the quality standards of choice table dates by being able to use the sub-standard fruit for date products. The initiatives were undoubtedly also inspired and helped by a strongly emerging prepared food industry in the U.S. in which the date producers desired to have a part. Many of the Annual Reports of the Date Growers' Institute in this period bear witness to this research both by private and public initiatives, and many of the products referred to in the previous paragraph had their roots in this development work (123, 124, 125, 302, 527, 31). With the gradual change of ownership of the date plantations and concentration of date products use in large multi-food companies, development work nowadays is largely done under cover of proprietary rights and does not come out in the open as it used to. This phenomenon is also confirmed by an increasing number of patent applications in this field.
In the Old World, Iraq has been the leading country in date products development, especially in the industrial use of the date. Its National Date Research Centre has operated for many years and hosted the Headquarters of the FAO/UNDP Regional Centre on Palm and Date during the period 1975 to 1985. North Africa has contributed to these developments though the main emphasis has been on improving (export) quality of table dates of the Maghreb countries and some industrial uses of low quality dates in Libya and Egypt. As will be remembered, most of Egypt's date crop is consumed fresh.
Over the last ten years Saudi Arabia has entered the field of research on dates, a parallel development to the strong promotional efforts by the Government to improve and increase date production and processing. The research activities are now centred at the National Date Palm Research Centre located at Hofuf, Al Hassa.
By 1971, 5,000 new products of all kinds were presented yearly to the U.S. supermarkets, an amount about equal to the available items of most supermarkets at that time (610). These numbers will probably have increased since then and it is obvious that only a few newly introduced products can survive in the long run. Proportionally, date products will be no exception as is shown from the experiences of date products that have vanished or have been replaced by newer developments. The European and local markets in the date producing countries will show similar signs and the conclusion is that the commercial introduction of a new date product is a tedious process which needs a thorough knowledge of customers' habits and tastes with regard to food, assured raw material supply and distribution systems, secured keeping quality of the product, potential market volume, and competitiveness with closely related products. In addition, trends in consumer preferences should be recognized and exploited by responding to them. It further needs capital and much promotional effort.
In the last twenty years there have been numerous attempts to improve existing formulae and develop new date products as reflected in the technical literature. However, little is known about the rate of success, i.e. whether the idea remained conceptional, or reached pilot scale production and marketing, or became a commercial success.
The following overview of research on date products development over the last twenty years or so is therefore given in the light of technical interest and perhaps as a source of ideas for date products promotion. For convenience and clarity the products have been classified in groups, reminding the reader that only the use of the date flesh, of comparable or nearly comparable quality as that applicable to whole dates, is considered in this chapter.
a. Whole pitted dates:
Various products can be mentioned that in some way provide a new use for dates in a date product. The first consists of a fig stuffed with roasted almond, a date, raisins and a bonbon, and then coated with chocolate (130). Another replaces the date pit with an almond, cooks the filled date in sugar syrup, thereby imparting a golden colour to the date and syrup (324). The preservation of dates in syrup is long known and practised but has also been the subject of additional development work. In these tests peeled and pitted dates were placed in 50° Bx syrup of which PH was adjusted by citric acid from about 7 to 3. The mixture was boiled down to Bx 75° , and various flavours (orange, banana, grapefruits etc.) added (275, 276). Whole, pitted rutab spiced with clove and cinnamon, stuffed with almond (if desired) are put into jars and a slightly acidified sucrose solution (70oC Bx) is added under vacuum to ensure good penetration of the liquid in the date cavity. After sealing, the jars are pasteurized for 20 minutes at 90oC in a waterbath (65). Another development involves an apparatus which combines pitting and filling the cavity of dates with a suitable mixture or almond in one operation. The resulting filled date, if desired, is then sent for coating with chocolate (312, 580). In analogy with the long established process for candied fruits, this technology has also been tried on khalaal (276, 506). Washed and pierced (to facilitate exchange of materials) khalaal were immersed overnight in a 35.5° Bx syrup (composed of equal amounts of sucrose and glucose syrup), of which the PH was adjusted to 2.8 by a mixture of citric and ascorbic acid. After briefly bringing to the boil, Bx content was increased by 5-10° at 2-3 day intervals until a Bx level of 75° was reached. Originating from a date of about 40% dry matter (of which about 84% was sugar), a product resulted of over 80% DM (of which about 86% was sugar).
Canning of khalaal has been the subject of a study (322) but no definite recommendations as to the procedure, which consisted of washing, pitting, blanching, can filling (with sugar syrup, citric and ascorbic acid), exhausting, sealing, sterilization and cooking, could be arrived at.
b. Pure date paste:
The technical aspects of making date paste are simple and is normally done in mincers. The fineness of the grind can be adjusted by changing dies with holes of different diameter. The texture (softness) of the product is mainly determined by moisture content, but not by this alone. Different date varieties of the same moisture content may produce a paste of different softness. Moreover, date paste will tend to get harder during storage, even when maintaining the same moisture content. Add to this the increasing risk of browning and fermentation with increasing moisture, it is clear that the characteristics of the raw material and the desired end product must be matched by technological manipulation. Evaluation, standardization, and storage stability of date paste were subject of a study (on one date variety: Ruzeiz) reported in two parts (607). The main results of these investigations are:
- moisture content can be satisfactorily adjusted (upward) by either steaming or soaking of the dates prior to grinding. (Normally one will start with dry dates for producing a paste of around 20% moisture. If dates of a high moisture content have to be turned into paste of 20%, dehydration would have to be applied.) Within the normally required range (say max 10% increase in moisture) during steam treatment (5 min.) and soaking (10 min. at 25° C) no significant leaching loss will occur,
- soaking of Ruzeiz dates (12.38% moisture) for 10 minutes raised the moisture content to 22.09% with water activity of 0.57, well within the safety limit for fermentation,
- Ruzeiz date paste of about 18% moisture (pre-steamed) and 22% (pre-soaked) stored at respectively 5° , 25° , and 50° C did not show appreciable difference in colour, PH and total sugar content for 16 weeks at 5° C, 8 weeks at 25° C and 3 weeks at 50° C,
- addition of 0.2% citric acid, which lowers initial PH from 5.96 to 5.40, perhaps desirable from an organoleptic point of view, does not significantly change storage stability except perhaps for PH at 25° C at which the paste remains more stable than the control,
- the same applies to addition of 0.2% citric acid + 0.2% ascorbic acid.
In the context of date paste making mention should also be made of several attempts to produce date paste sheets, named tamaruddin in analogy with the well-known and widely distributed apricot "leather" (quamaruddin). There are, however, two basic differences between the two raw materials, which makes the date the less favourite for such a product. Whilst the apricot can be turned into sheets from its natural state by pulping, screening and drying on boards, dates have to be diluted first to be pulped, after which the water has to be evaporated again. Secondly, the date's natural less pronounced flavour and acidity make it less suitable as a base for a reconstituted drink for which this paste is mainly used. The experiments carried out (379, 388, 389) reflect these shortcomings which have been tried to overcome by addition of organic acids, and/or other fruit pulps and flavours. In this way fruit pulp mixtures are created which under certain conditions may find a place in the market or as a semi-finished product (see iii).
c. Date paste mixtures
With the possibility of producing a date paste with the desired moisture content, texture and softness well in hand, the field to combine and supplement this basically sweet material with other foodstuffs is wide open and many proposals have been made:
- premixed date bar (including almonds and corn starch) supplemented with respectively soy protein isolate (SPI), single cell protein (SCP) and dry skimmed milk (DSM), resulted in a nutritional balanced mixture and scored well with moderate variations in sensory testing compared to control, also after prolonged storage (up to 6 months) at 7° C and 25° C. Similar product mixes based on protein supplementation by SPI, SCP and DSM have been reported (270, 259, 496, 144), as well as date paste/roasted peanut mixtures (487, 578). All these studies were aimed at creating acceptable, nutritious snacks for children.
- nutritious candy bars based on date paste mixed with corn starch, whole dry milk, roasted almonds, coconut, sesame butter and milk chocolate (as coating), in various proportions. Date paste constituted from 74-84% of the final weight according to recipe (6 in total). Moisture content ranged from 14.9-16.6%, protein 4.78-5.98% and fat 7.28-15.17%. Sensory testing showed a preference for chocolate coated bars. Storage tests showed a decline in quality after two months at 40° C and five months at 28° C, whilst the samples stored at 5° C remained unchanged (604).
- tamrina, a protein-rich food mixture for feeding infants and pre-school children (600) is based on a variety of mixtures of wheat, lentils, chickpeas, dates, milk powder and vitamin supplements. The process is as follows: wheat, lentils and chickpeas are cooked for 15-20 minutes with just enough water for total absorption. The cooked mixture is then dried at 70° C on trays in a drier. Pre-dried pitted dates (50° C) are mixed in and the total mass ground to 70 mesh. The other ingredients (milk powder and vitamin supplement) are added and the whole mixture is packed in aluminium lined polythene and stored at 4° C and room temperature up to 6 months. Dates constitute 10% of the mixtures before preparation. The final products, varying according to the recipe, range 5-6% in moisture, 19-20% in protein, 2-5% in crude fat, 10.5-14.5% in sugar and 45-47% in starch. Organo-leptic evaluation was favourable, even after six months storage. The product was created with the intention of using as many locally available materials as possible and substituting sugar for dates.
- tamarheep (a contraction of tamr (date) and haleep (milk) is an effort to create nutritionally balanced date mixtures following the process of apricot leather, i.e. pulping, screening, mixing and drying into sheets (see ii). In the experiments under review (380), apricot leather was compared with pure date leather and a number of date leathers reinforced with skim milk powder (DSM) (respectively 20, 35 and 50 gm to each 300 g date pulp, which corresponds to 120 gm of dates). In addition the basic tamarheep (i.e. dates + DSM) were flavoured with different fruit flavours and the resulting multitude of products were tested by a taste panel. General conclusions were a preference for apricot leather but good appreciation for tamaruddin (date leather) and plain tamarheep and some of the fruit flavoured tamarheep, either in solid form or reconstituted.
A chocolate and vanilla flavoured drink from a whey/milk mixture sweetened with date puree and sugar was successfully tested and rated well compared to the control based on sugar only (200).
d. Date paste in bakery products and confectionery
The use of dates and date pieces in bakery products and confectionery has been reviewed earlier in this Chapter and several commercial products, mainly of American origin, were identified. The use of date paste for this purpose is much less common and was investigated for possible application in bread and cookies by large-scale modern bakeries (370, 605). In these experiments wheat flour (12.40% moisture, 13.07% protein, 1.33% fat) was replaced by date paste (15.82% moisture, 78.24% total sugars, 2.24% protein, 0.35% fat) at the respective rates of 0, 4, 8, 10 and 12% in bread. For cookies 0, 10, 15 and 20% replacement was adopted with corresponding adjustment of sucrose addition to keep total sugar constant in all samples. Overall outcome of testing the resulting samples was:
- bread specific volume was highest at 8% addition of date paste
- at 12% the dough is sticky and typical bread characteristics are distorted
- sensory testing by a taste panel revealed a preference for the control (i.e. 0% date paste) on all test criteria (crumb texture, appearance and flavour) for the bread samples
- in the case of cookie testing the results were opposite with highest rating for 20% addition of date paste
- cookies showed less tendency of cracking with increasing paste content
On the basis of these results it would therefore seem that application of date paste in cookies will have a better chance of success than in bread making.
In another study (395) replacement of 50% sucrose by date paste in cookies resulted in, besides the organoleptic improvement, a higher moisture retention and prolonged shelf life of the product.
e. Date preserves
Preserves are normally understood to be derived products created to prevent spoilage of fresh foodstuffs in order to extend their storage life and availability to the consumer. Common natural auxiliary materials to assist in this process are sugar, salt and (organic) acids.
Though dates at the tamr stage would not necessarily fall into the fresh food category because they are self-preserving, several date preserves have been experimented with or reached commercial application, perhaps more for the purpose of broadening the date product choice than for the effect of preservation.
Fruit jams are one of the most common preserves and the process consists of boiling fruit or fruit pieces with sugar to a consistency where microbes are not able to grow. If required, pectin is added to secure gelling and the PH is adjusted by citric or tartaric acid. The resulting product is hot filled in jars or cans, closed, and usually pasteurized in a hot water bath. Upon cooling the product will gel. Densities may range from about 60 to 70° Bx and a PH in the range of 3.2 - 3.5. Most food laws require a minimum percentage of fruit pulp in the final product.
Dates are, because of their natural composition, not the most adaptable type of fruit for jam making because of their high sugar content, their comparatively high PH and less pronounced flavour. Naturally occurring pectin varies with the type of date and normally needs to be supplemented especially when a lighter type of jam is desired. Several research institutes have therefore analysed varieties and experimented with date jam making to find the most suitable types and recipes (553, 276, 330, 331, 498, 367). A typical date jam recipe and analysis is as follows:
Khudairy date jam, Saudi Arabia (355)
(62.4% date flesh) 55 kg
Sugar 45 kg
(as % of dates in pulp) 1.02
Mixture boiled down to Brix 66-68°
Analysis: PH 3.7, Brix 67.2° , Date/Sugar ratio + 0.75
In testing the suitability of dates at the different stages of maturity (khalaal, rutab and tamr) it was found that rutab lends itself best for jam making before tamr, whilst khalaal should not be considered for its low solid content and lack of specific date flavour (357).
With the present overall trend to produce lighter jams of less sweetness there may be scope to finish the jam at a lower Brix (within the limit of the law) and to consider dates combined with other fruit mixtures to create specific flavours.
A product slightly different from date jam, named date-butter, was made experimentally with the aim of, a.o., creating a semi-finished product for further use by industry such as confectioners. The difference with date jam consists mainly in a higher date/sugar ratio, lower acidity (PH 4.6) and higher final Brix (around 75° ) (276). Along similar lines as experimented earlier (125), canning of date pulp was attempted for eventual use as a semi-finished product for the food industry. Difference with the date jam and date butter processing is that no cooking takes place. Best results were obtained by blending date pulp (made of steamed dates) with a 20° Bx sugar solution or date liquid sugar solution. This blend is homogenized, adjusted for PH (3.9), packed and sealed in cans and sterilized, because the product is perishable (around 50° Bx) (335).
Whilst raising the sugar content of food to a high level is a form of preservation to exclude microbial growth, pickling consists of both controlling some and encouraging growth of other microbes (not harmful to humans), in order to reach a situation in which the product is both preserved from microbial deterioration and remains edible. To reach this condition quite often use is made of salt which selectively controls microbial growth. Examples are fermented cabbage ("sauerkraut") and a wide variety of pickled fruits and vegetables, like gherkins, cucumbers, cauliflower, olives etc. However, high sugar containing fruits like deciduous fruits, are not suitable for this type of preservation and the fully mature date therefore would not seem a promising candidate. Nevertheless, some work has been done and the first interest has focussed on the pickling of dates at the kimri and khalaal stages, i.e. when they are perishable, low in sugar, high in moisture and mostly astringent. Up to a point the comparison with olives is valid, except that olives have a high oil content.
A first report on the subject (277, 276) deals with a method, called fresh-pack pickle, which does not involve fermentation, because dates are packed in an acidified sugar solution and immediately pasteurized. Other particulars of this experiment were: 3 varieties of dates at the kimri stage were washed, peeled in an abrasive drum peeler, hand pitted and cut in slices. They were packed in a 20% sugar solution with a varying (acetic) acid level (2.0, 2.5 and 3% of a 5% standard acid strength solution respectively). 3% salt, 1.5% spices and 0.05% sodium benzoate were added to all samples. Pasteurization time and temperature were also varied but proved optimal at 71° C for 15 min.
Major results of these tests were:
- after 3 months storage, total acidity in the solution drops and PH values increase; total soluble solids decrease. These changes level off sharply in the period up to 6 months storage. Conclusion: product has stabilized after 3 months
- in sensory testing no clear preferences for either variety or acidity range could be detected and all samples came out as acceptable for colour, taste and texture in the range of 7 (out of 10)
In a sideline of the above main experiments one variety was stored in salt solution for 2 months before being used as salt-stock in the main experiment. The preparation of the salt-stock went as follows: dates were covered with 12% salt solution, which after one week was raised to 15% and maintained until stabilization. After two months at ambient temperature the dates were removed, washed several times with running water to remove salt, and further treated as for the fresh-pack pickle. The initial acidity of the salt-stock as lactic acid was found to be 0.49% which is considered low though it shows fermentation had taken place. In the analyses of the subsequent pickles derived from this salt-stock according to the fresh-pack recipes, the decrease in total acidity, increase in PH was not so pronounced as for fresh-pack pickles after 3 and 6 months storage, but the decrease of total soluble solids in solution followed the same pattern.
Other experiments on kimri and khalaal pickling resulted in satisfactory products using 15% salt solution and 2% acetic acid after 6 weeks for kimri (417) and 10% brine plus 2% acetic acid, boiled for 5 minutes, for khalaal (603).
In another effort of date pickling (201) dates were pickled following two methods: "fresh brine pickling" and "salt-stock pickling".
In the fresh brine pickle dates (kimri stage, 70% moisture, PH 6, Bx 16-18° ) were given two vertical cuts and placed in jars covered with 32° Salometer salt solution (n.b. 100° Salometer corresponds to 25% salt solution) and 2% vinegar (of 4.5% strength) was added. In a parallel lot the fruits were cut but no vinegar added, and in a third lot the fruit was not cut but brine and vinegar were added. After 90 days of fermentation the brine solution (32° ) is renewed including 5% vinegar, packed in jars and sealed, and pasteurized at 80° C for 15 min. in hot water.
In salt-stock pickling the fermentation is started with 32° salt solution, after which at weekly intervals 2% salt is added until after 4 weeks the solution has reached 60° Salometer. After 90 days the fruits were freshened with warm water for 8 hours at 50° C (repeated twice). Fruit is then treated as for fresh brine pickle at the second stage. In both methods some lemon and dill were added for extra flavour.
Main results of this study were:
- in spite of rather slow fermentation rate (12 weeks) in fresh brine pickling, acceptable PH (3.45 - 3.85) and total acidity levels (0.80 - 0.90%) were reached, the samples with vinegar having the higher acidity levels
- in the salt-stock pickle it took up to 24 weeks to reach the extreme acidity levels of the fresh brine pickle
- cutting the dates or not had no appreciable influence on the process
- samples to which vinegar had been added were preferred in all cases during sensory testing
- the addition of lemon, dill and stuffing of piemento red pepper enhanced the acceptability of the product
- a negative comment on quality concerned the toughness of the pickle
It is evident that with these experiments, valuable as they are, the possibilities of pickling dates at the kimri and khalaal stages have so far not been exhausted. The process variables and techniques, the sugar/salt/acid ratios and the use of additional flavours are numerous and provide many opportunities for extended research in this area. Attractive, appetizing date pickles could become a welcome addition to the date product variety and date outlet possibilities.
f. Date condiments
A condiment is characterized by a specific flavour and is used to give relish to food. In Heading 3 of this Chapter several commercially available condiments containing dates were identified. Two additional efforts to incorporate dates in condiments are referred to: they are concerned with date chutney and tomato ketchup. Chutney is a generic term of a condiment composed of a sweet (provided by fruits), acid (provided by lemon or vinegar), vegetables and (hot) spices. Chutney (derived from the Hindu chatni), is probably best known when mango is used as the basic fruit, but also apple, tomato and mixed fruit chutneys are known, so why not a chutney predominantly consisting of dates? In trying this, 6 prototype samples of date chutney were prepared (276, 505) in which the following ingredients were incorporated:
- dates: either as chopped pieces or as pre-prepared pulp
- vegetables: carrots, onions, piemento
- spices: ginger, cayenne pepper, paprika, coriander, cinnamon
- vinegar/acetic acid
- other additives: salt, casein powder, gum arabic, water
The preparation of these chutneys consisted of boiling the carrots, chopped dates and raisins with water and date pulp for 15 minutes after which the sugar and seasonings were added followed by a further boiling for 20 min. The major characteristics of the samples were: PH 3.57-3.65; Brix 50.2-51.2° ; Total sugars 35.4-37%; Acidity (as acetic acid): 1.22 - 1.39%.
In sensory evaluation (15 panel members) no significant preferences for one or more of the 6 samples came out but the overall appreciation of the product was favourable.
Tomato ketchup (derived from the Chinese Koe-chiap) is now mostly known as a sauce of homogenised tomato pulp mixed with sugar, vinegar, salt and flavouring (sometimes hot spicy). In an attempt to make more and better use of local resources experimental work was carried out (336, 337) to substitute sugar for dates in tomato ketchup. Starting from a standard recipe which contained tomato juice, salt, sugar, vinegar, pectin, onion and a number of condiments (garlic, red chillies, paprika, nutmeg, cloves, cinnamon, cardamon, ginger, coriander, and aniseed), the preparation of the ketchup consisted of extracting tomato juice from fresh tomatoes (heating in water, straining) mixing in the other ingredients and boiling down to the required Bx content. Major characteristics of this standard sample were: Dry matter 33.9% (Bx 32° ), PH 3.62, acidity (citric acid), 1.16%, sugar total 26.5%. In the preparation of the test samples sugar was progressively replaced by date pulp (prepared from steamed, pitted, homogenised dates mixed in equal mounts with a 20% sugar solution, slightly acidified with citric acid). The rates of sugar substitution were respectively 25, 50, 75 and 100%. The chemical composition of these samples, as a consequence of this substitution, showed a slight increase in PH and reducing sugars, and increasing mineral, crude fibre and fat contents. The results of the test panel according to the report, showed no significant difference in colour, flavour and consistency of the various samples, but was not conclusive on overall taste.
g. Date desserts
Past records (302, 123) make mention of development work on the use of dates in desserts, like ice cream and puddings and some of these products have reached commercial application, the extent of which is difficult to judge but mostly concentrated in the U.S. More recent development work has also been done in the Arab World as part of the overall effort to provide more diversified marketing outlets for the date fruit.
The following examples are quoted: dates in the form of date juice (diluted and strained date paste), were used at different levels as sweetening and flavouring agent in water ice, fruit sherbet at 20, 25 and 30° Bx and ice cream. From a technological viewpoint the following results were obtained: Overrun (i.e. the percentage increase in volume of the mix caused by beating-in of air) as well as viscosity increased with higher Brix. Increasing Bx content from date juice reduces meltdown time, however. The sensory evaluation revealed no significant difference in water ice for flavour, body/texture and colour, hence the lower level of 20° Bx at the different Bx levels could be considered sufficient. For fruit sherbet and ice cream a statistically significant preference with regard to flavour for 20° Bx addition was observed equalling the rating for the control ice cream (15% sucrose). General result of these tests are therefore that date juice at 20° Bx can replace sucrose partially or completely in water ice, fruit sherbet and ice cream (532).
In a similar experiment strained and unstrained date juice derived from date paste was used to replace sucrose in ice cream at the rate of 17, 34 and 50% (w/w of sugar value) respectively. These substitutions created an increase in freezing time and decrease in overrun for unstrained date juice. However for strained date juice (through cheesecloth, which removes skin particles and coarse fibre) this was not the case. Melting time was increased with increasing amounts of sucrose replacement and melting quality remained stable in all samples. Sensory testing rated ice cream with highest sucrose replacement (50%) as significantly best. In a parallel test date chips were added to ice cream at the rate of 5, 10 and 15% to the control sample (0% sucrose substitution). Percentage overrun was decreased (from 80 to 75% for 15% addition of chips), freezing time was not affected, but melting time was increased. Sample with 10% chips were rated first in sensory evaluation (203).
Dates combined with yoghurt has not received much attention in date products research, which is somewhat surprising whilst the yoghurt fruit combinations on the market nowadays are numerous. The popularity of these products has brought about the establishment of a specialized industry which at the client's preference prepares fruit mixtures, ready for incorporation in yoghurts, confectionery and ice creams. However, so far dates have not played an important role in this development. One study (464) focusses on incorporating dates (tamr) in an existing product made of fermented and dried milk (oggt), creating a new product tamroggt. Oggt is a traditional preservation technique for milk, which is fermented, churned, the butter removed and the remaining butter milk is boiled down to a paste. This paste is formed into patties which are further dried in the sun. Moisture content in these traditional products may range from about 4 to 8.5%, fat from 16-23% and protein from 44-48%. In the experiment oggt was made from reconstituted skimmed milk powder, thus by-passing the churning process, and using a common yoghurt starter. Boiled down to a paste, pitted, chopped dates were added in different proportions and the samples dried at low temperature.
The sample in which equal mounts of dates and skimmed milk powder were present had the following composition: Moisture 10%, protein 25%, total sugar 60%. In two other samples the date ratio was cut by half and replaced respectively by 0.1% anice and 0.2% sesame seed in one, and 1% cocoa in the other. In sensory evaluation, the cocoa flavoured sample did not fare well; the tamroggt with anice/sesame addition came out highest, followed by tamroggt and the control oggt.
The use of dates in puddings has already been referred to earlier but it seems appropriate to conclude this chapter on "Date fruit products and preparations" with a recipe of such a dessert, because the proof of the pudding is in the eating, as the English saying goes. And that applies to all the date products and preparations which have been reviewed in this Chapter.
Spiced date bread pudding (465)
2 cups warm milk, ½ cup sugar, ¼ tsp salt
1 tsp freshly grated nutmeg, ¼ tsp vanilla
½ cup pineapple or other fruit juice
Mix and pour over 2 cups cubed day-old bread, soak for 10 min. and stir in three quarters of a cup of chopped dates, 3 beaten eggs, and half a cup nutmeats.
Bake pudding in greased baking dish, set in a pan of hot water in moderate oven (350° F, 175° C) for about 1 hour. Serve hot or cold with cream.
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