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Efficient enzymatic conversion of lactose in milk using fungal?-galactosidase
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Abstract: ?-galactosidase (?-gal, E.C. 3.2.1.23) was detected in different fungal cultures and their fermentation factors wereoptimized, as well as ?-gal was purified and characterized from the selected fungal strain. Moreover, the potential impact of fungal ?-gal on free lactose-flavored milk production was investigated. Aspergillus terreusNRRL 280showed the highest ?-gal specific activity which grown at 37 ?C for 7 days compared to other fungal strains. Also,A. terreusNRRL 280 showed their highest ?-gal activity at the optimized growth conditions of 37 ?C, pH 4.0 for 7days. ?-gal enzyme was purified from A. terreusNRRL 280 using 40-60% ammonium sulfate saturation with22.15% yield and 1.11 purification fold. Purified ?-gal exhibited their optimal activity at 60 ?C, pH 6.0, and 80min of incubation time, as well as it was is quite stable for the heat treatment. ?-gal activity was significantlyenhanced with 5 mM Ca2+, Mn2+ and Mg2+, while it was were sensitive to Fe3+ and EDTA. The highest lactosehydrolysis (94.16%) and 23.9 g/l of glucose were recorded for flavored raw skim milk treated with 7.0 U/l milkof ?-gal at 6th day of storage period. The flavored milk made from raw full cream cow milk treated with 5.25 U/lof ?-gal was recorded the highest sensorial attributes scores followed by those of made from raw skim milk withthe same ?-gal level. It could be concluded that using of fungal ?-gal in lactose-free flavored milk may prove to bebeneficial for intolerant lactose people.
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| Publication year |
2020
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| Author(s) from ARC |
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| External authors (outside ARC) |
أسامة عبد الحميد ابراهيم
قسم علوم الالبان- المركز القومي للبحوث
عبير السيد عامر
قسم ميكروبيولوجيا الالبان-معهد بحوث الانتاج الحيواني- مركز البحوث الزراعية
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| Publication Type |
Journal
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