الفهرس 
الغلافOnly 14 pages are availabe for public view
 |  | from | 312 |  |  |
| | | from | 312 | | |
Abstract
This study was carried out to investigate the physio-chemical properties and quality attributes of different date products: Tamr-Eddin Date Sheets ’’IDS’’ prepared by two different methods (conventional oven! solar energy) , Date Syrup ”Dibis” , Date Gel ”Pudding and Jelly” which prepared from three different soft dates varieties in Egypt (Zaghloul - Samany - Hayany) at khalal (colored) stage of maturity. Results of date varieties showed that, pH value ranged from (6.16 - 6.34), and TSS averaged (26.25 - 30.95 °Brix). Samany date tended to have higher ”L” and ”b” values, while redness ”a” values were higher in Zaghloul and Hayany. Chemical composition of dates indicated higher moisture (63.25 - 68.63%) and total sugars content (22.7 - 29.64 %). Reducing sugars were the predominant sugars ranged between (17.31 - 23.08 %). However, they contained moderate percentages of protein, fiber and ash. Phytochemical analysis showed that Hayany possessed higher total anthocyanin ”T AC” and carotenoids ”TC” contents [1.905 (mg/100g) and 0.754 (mg/L) , respectively], while total phenolic ”TP” content was higher in Zaghloul date (60.67 mg GAE/kg). However, Samany showed lower phytochemical contents. With regards to mineral composition, potassium was found to be the most abundant element with a concentration of (391.92 - 464.62 mg/IOO g), followed by phosphorus and calcium in the three investigated date varieties. Dates also have moderate concentrations of iron (0.62 - 0.71 mg/IOO g) and zinc (0.29 - 0.34 mg/100 g). However, Zaghloul cultivar contained the highest levels among all the investigated minerals compared to Samany and Hayany. Physical properties of date products indicated that total acidity was lower for all products, except for date syrup (dibis). Color evaluation showed that Samany and Zaghloul TDS without fiber tended to have lighter yellow color than Hayany, whereas TDS with fiber in conventional oven had darker color than those prepared by solar energy. On the other hand, date syrup (dibis) showed more attractive colors (foxy-red in Zaghloul, bright orange in Samany and dark red for Hayany). However, Lab parameters for date gel (pudding and jelly) with date juice showed higher ”L” and ”b” values, while date gel colors were similar to the syrup prepared from it. Purity (%) and viscosity (c.p.) values were higher in date syrup with 0.5 % citric acid. Line spread test and syneresis values of puddings with juice were higher than those with syrup. Date jelly prepared with Hayany juice and syrup had the highest value for percent (%) sag. Sugar composition (total, reducing and non-reducing sugars) indicated that reducing sugars were the predominant sugars for all the prepared date products. Phytochemical analysis of different date products showed that processing methods had no great effect on total phenolic (TP) content. However, carotenoid content was affected by the heat treatment that was (50°C) for date sheets and about (90 0c) for date syrup and date gel. Also, Anthocyanin was slightly affected by processing methods in conventional oven and solar energy. The addition of citric acid increased total anthocyanins (T AC) and total carotenoids (TC) contents of date syrup from three date varieties compared to samples without citric acid. Organoleptic evaluation showed that (Tarnr-Eddin Date Sheets ”TDS” without and with fiber in both conventional oven and solar energy - Date Syrup ”Dibis” without and with 0.5 % citric acid - Date Pudding with Juice) prepared from Samany showed the best organoleptic characteristics, as well as date gel samples (Pudding with Date Syrup ¬Date Jelly with both Juice and Syrup) prepared from Zaghloul were the most acceptable. Nutritive evaluation, including major components (%) and mineral composition (mg/IOOg), were studied for Date products which maintained the best organoleptic properties. It showed that sugars, especially reducing sugars, were the main components in all date products except for the date gel samples (pudding and ¬jelly) which possessed higher moisture content. However, Samany date syrup (Dibis) had higher content in potassium (K), calcium (Ca), phosphorous (P), iron (Fe) and zinc (Zn). The present study recommended the production of novel date products such as Tarnr-Eddin sheets (TDS) with and without fiber - Date syrup (or Dibis) - Date Gel (pudding and jelly) from Zaghloul, Samany and Hayany at khalal stage of maturity. In addition, the present study recommended that Food industries should be encouraged to consider these prepared Date products among their food development strategy.