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Abstract
Date is one of the most important crops cultivated in Egypt as a results of the suitable conditions to its cultivation , so there are a large area were cultivated by dates. The exported dates of Egypt were less than 1% of the total production ,the Egyptian dates divided to three types ( soft date , semi dry date and dry date ).The first type ( soft dates ) represented 36.8% of the total production ,the second type ( semi dry dates represented 20.4 % of total production and the third type ( dry date ).
The soft date was the highest moisture content so it decays quickly so that it could be preserved by using different methods. Soft date varieties during rutab stage represent a strong problem during paste production where date peels are difficult to remove. Date fruit has a high content of sugar ,while its content of protein and fat is very low, so we try to supporting date fruit by different sources of protein ( dried skim milk ,sesame, peanut and soybean ) were add to improve the nutrition and caloric values of date.
This investigation was carried out to compare the effect of different methods of drying on the quality parameters of date .Also to improve the nutrition and caloric values by supporting date by different protein sources to produce some high quality date products. Third aim of this investigation is suggesting a simple solution for peeling problem during rutab stage of soft date
To achieve the goal this study ,Hayany date was collected in two maturation stages ( khalal and rutab ). The Hayany khalal date was divided into two groups the first was peeled by carborandum then maturated artificially by acetic acid ,the second was dried by oven 90°Cwithout peeling
Hayany rutab stage was peeled and pitted then divided into four parts ,the first part was used for sun drying by laded on paper and turned off every day and covered nightly for four days then processed to pastes and turned off for three days and packaged in polyethylene bags, (Traditional method)
The second part was used for sun drying by laded on net and turned of every day and covered nightly for four days then it was processed for pastes production, which were turned off for three days and packaged in polyethylene bags.
The third part was dried by oven at 60 °C for 5 hr and packaged in polyethylene bags.
The fourth part was dried in greenhouse for 4 days on net and then used for processing pasts which dried completely on wooden trays (75+150 cm ) for three days thin packaged in polyethylene bags.
Amry dates variety (semi dry dates) at Khalal stage were divided into four parts .The first part was dried in sun drying and turned off every day and covered nightly for 15 days.
The second part was dried in oven at 60°C for 24 hr and packaged in polyethylene bags.
The third part was dried in greenhouse on wooden trays(75+150 cm) for10 days ,it was turned off every day
The fourth part was dried in oven at 90°C for 5hr and packaged in polyethylene bags.
The obtained results could be summarized as follow
Physical properties
Results showed that the number of fruits in one kg was 65/kg in khalal stage and 68/kg in rutab stage for Hayany date and 60/kg in khalal and100/kg for Amry tamr date
Results demonstrated that the mean weight of flesh fruit was 13.5 g in khalal stage ,11.1 in rutab stage for Hayany date and 14.8 g in khalal stage ,8.6in tamr stage while the weight of pit was 1.8 g for Hayany date either in khalal stage or rutab stage and 1.3 – 1.7 g for khalal and tamr in Amry date, respectively . The flesh percentage in khalal stage was 88% in Hayany date and 89 % in Amry date.
The fruit color was changed from red in khalal stage to black in rutab stage for Hayany and ,also changed from red yellow in khalal stage to brown in tamr stage for Amry .
Results in this investigation showed that the firmness was increased in Hayany date after using of drying methods, while the firmness was decreased after using of drying methods in Amry date
Chemical characteristics
Results showed that the moisture ,ash ,crud fiber and reducing sugar contents of Hayany date in khalal stage were higher than those of Amry date while the total sugar ,acidity, tannin and pectin content were lower than those of Amry date.
- The chemical composition of Hayany date after drying recorded a decrease in moisture and tannin in all treatments while ash ,pectin acidity , color( optical dinesty) and crud fiber increased in all treatments except the crud fiber in the sun drying on net
- Also the results of chemical composition of Amry date in moisture ,tannin , ash and crud fiber after drying in all treatments while ,pectin acidity and color increased
- The total and reducing sugars of Hayany date recorded decrease after drying compared with traditional sample where the peelin by crborandum treatment recorded the highest decrease while the greenhouse recorded the lowest decrease
The total and reducing sugar of Amry date were increased after drying compared with fresh sample ,where the greenhouse drying recorded the highest increase while the oven drying at 90°C recorded the lowest increase
Chemical characteristics of date products after supporting by different sources of protein
- The moisture content of Hayany and Amry dates products decreased in all treatments where the peanut treatment ( with coconut flavor) , recorded the highest decrease from 11.6 to 9.2 % and from 12.8 to 11.2 either Hayany or Amry date, respectively.
- The ash content of Hayany and Amry dates increased after supporting by different sources of protein where the skim milk treatment ( with cinnamon flavor ) recorded the highest value of ash content either for Hayany or Amry date
- The total carbohydrates of Hayany and Amry dates products decreased in all treatments where the sesame treatment ( with coconut flavor) , recorded the highest decrease in Hayany and Amry date
- The total protein of Hayany and Amry dates products increased in all treatments ,where soybean treatment recorded the highest increase (9.5%and 9 %) in Hayany and Amry dates (with cinnamon flavor ), respectively.
- The fat content of Hayany and Amry dates products increased in all treatments ,where sesame treatment recorded the highest increase (10.5%and 12.6 %) in Hayany and Amry dates (with coconut flavor ), respectively.
- The caloric value of Hayany and Amry dates products increased in all treatments ,where sesame treatment recorded the highest increase (410 and 427.8) in Hayany and Amry dates (with coconut flavor ), respectively.
Sensory properties
Concerning to sensory properties ,the obtained results showed that , oven drying at 60°C recorded the best organoleptic characteristics for Hayany date ,while greenhouse drying method was the best for Amry .
The sensory evaluation of Hayany and Amry dates products after supporting by different sources of protein ( skim milk ,sesame , peanut and soybean )demonstrated that
1- supporting Hayany date by sesame resulted in an improvement in sensory parameters of the obtained products either flavored by coconut or cinnamon
2- supporting Amry date by peanut resulted in an improvement in sensory parameters of the obtained products either flavored by coconut or cinnamon