Ultraviolet radiation enhanced growth of lactobacilli and their bioconversion of isoflavones in biotin-supplemented soymilk

作者：Ewe Joo Ann; Wan Abdullah Wan Nadiah; Alias Abdul Karim; Liong Min Tze^*

来源：LWT-Food Science and Technology, 2013, 50(1): 25-31.

DOI：10.1016/j.lwt.2012.07.042

• Ultraviolet
• Lactobacillus
• Biotin-soymilk
• Isoflavone
• Cellular membrane

The aim of this study was to evaluate the effect of ultraviolet (UV) treatment on growth of lactobacilli and their bioconversion of isoflavones in biotin-soymilk. Strains of lactobacilli were treated with different types of UV radiation at various doses prior to inoculation in biotin-soymilk. The impact imposed by UV treatment on lactobacilli was species/strain dependent as observed in the various parameters measured. Generally, the treatment induced oxidative damage on lactobacilli which decreased cell viability immediately after treatment. This was attributed to the increased oxidation of acyl chains and proteins in the membrane lipid bilayer, leading to increased lipid peroxidation and membrane permeability (P %26lt; 0.05). The alteration in phospholipid structures also reduced cellular membrane fluidity (P %26lt; 0.05). After removal of UV radiation, the cellularly injured bacteria cells were able to adapt, recover and resume growth during fermentation in biotin-soymilk (P %26lt; 0.05). UVB treatment of lactobacilli at 60 J/m(2) showed higher intracellular and extracellular beta-glucosidase activities (P %26lt; 0.05), leading to increased bioconversion of isoflavones glucosides to aglycones in biotin-soymilk. Results from this study showed that UV radiation could be applied to promote beta-glucosidase activity of lactobacilli cells for the development of aglycones-enriched biotin-soymilk.

• 出版日期2013-1