ASSESSMENT OF SOME SUDANESE FOREST FRUIT EXTRACTTO ENHANCE THE QUALITY CHARACTERSTICS OF BEEF BURGER

Abstract

This research aimed to examine the effects of adding forest fruit extracts to beef ―burger‖ to enhance it‘s quality characteristics. Six of the most common indigenous forest fruits in Sudan (Doum, Aradaib, Godeim, Tabldi, Lalob and Nabag) were subjected to physiochemical, phytochemical and antimicrobial activities investigation. Burger treated in three concentrations of 0.5 %, 1% and 1.5% using Lalob, Aradaib and Tabldi The treated beef burger and control samples were stored at 4°C and subjected to microbiological, physical and chemical analysis, Peroxide Values (PV) as well as sensory evaluation at 0 time and then at 2 days intervals for 6 days. Forest fruits contain considerable values of carbohydrates and fiber.However, the protein and fat levels were relatively low. GC-MS analysis of the ethanolic fruit extracts revealed the presence of alkaloids, glycosides, tannins, steroids, terpenoids, carbohydrates, small hydrocarbons, fatty acids and organic acids . Lalob exhibited the highest total polyphenols and total flavonoids contents which were 89.38 and 62.04mg/g, respectively, while Godeim scored the lowest values 36.19 and 26.90mg/g, respectively. Antimicrobial activities of the fruit extracts were investigated against E. coli, Staphylococcus aureus and Salmonella using agar-well diffusion technique. Aradaib extract exhibited the highest activity against E. coli and Salmonella (inhibition zones 11.10 and XVI 7.88 mm respectively), while, Lalob showed the highest inhibition zone (9.97mm) against Staphylococcus aureus. Lalob, Aradaib and Tabldi were noticed to produce the highest inhibition zones among the six fruit extracts examined therefore; they were selected for treating beef burger.Microbial growth of the treated burger decreased significantly (P<0.05) with increasing fruit extract concentration. Samples treated with 1.5% Aradaib extract showed the lowest Total Viable Bacterial Count (TVBC) 2.28 log10cfu/ml, while 1.5% Lalob recorded the lowest Total Coliform (TC) 0.52 log10cfu/ml and the lowest Yeasts and moulds 0.28log10 cfu/ml. The highest E. coli, Staphylococcus aureus and Salmonella counts were recorded for 0.5% Tabldi. The microbial count of all treated samples were significantly (P<0.05) increased with the storage period. Spoilage of burger treated with 1.5% Aradaib, 1.5% Tabldi, 1.5% and 1% Lalob extracts by E. coli and Staphylococcus aureus was delayed until the 6th day of storage. Salmonella was not detected during storage of all samples treated with 1% and 1.5% concentration. Yeast and moulds were detected only at the end of storage period (6th day), the highest growth counts were recorded for samples formulated with 0.5% Aradaib. Lalob was found the most effective as an antimicrobial agent followed by Aradaib then Tabldi. The treated burger samples recorded higher moisture, protein, fat fiber and ash content and lower pH values, and higher Water Holding Capacity (WHC), less cooking loss and less shrinkage compared to control. Burger formulated with fruit extracts showed negative effects on color as the level of fruits extracts increased. 1.5% Aradaib scored the lowest color values which were 16.13, 12.14 and 3.86 for lightness (L*), yellowness (b*) and redness (a*) respectively. Panelists preferred appearance and flavor of control than treated samples. All sensory attributes decreased significantly (p>0.05) with storage period. The fruit extracts exhibited antioxidant activity which was observed in the peroxide value reduction with the increase of fruit extracts concentration.It is XVII concluded the clear improvement in the quality characteristics of the beef burger treated by Aradaib,Tabldi and Lalob extracts .