Determination of Heat Inactivation Methods Towards the Antioxidant Activities of Paraprobiotics under Simulated Gastrointestinal Conditions

Ngui, Oscar Kai Jin (2024) Determination of Heat Inactivation Methods Towards the Antioxidant Activities of Paraprobiotics under Simulated Gastrointestinal Conditions. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

cells in the human body. This study aims to determine the antioxidant activities of different probiotic species and the paraprobiotics after conducting the heat inactivation method. Besides that, it is to determine the antioxidant activity of paraprobiotics before and after the simulated gastrointestinal digestion conditions. The project is conducted using four probiotic strains which is L. casei ATCC 393 (LC), L. salivarius ATCC 11741 (LS), L. plantarum TAR4 (LP) and Bifidobacterium lactis (B). The probiotics are standardised to 107 CFU/mL before undergoing three antioxidant assays, which is Ferric ion reducing antioxidant power (FRAP) assay, ABTS assay and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay. After that, heat inactivation will be conducted on the probiotic strains, and three antioxidant assays will be conducted. Based on the results, FRAP assay indicates that only B showed an decrease of antioxidant from 0.027 to 0.022 FRAP value while the other three showed increase in antioxidant from 0.240 to 0.300 FRAP value. The decrease could be caused by degradation due to high heat. ABTS assay showed that all probiotics have increased antioxidants after heat inactivation such as from 12.81% increase to 17.56%. The highest antioxidant producing probiotics strain is then chosen to conduct the antioxidant assay under simulated gastrointestinal digestion conditions which is LS. The result shows that antioxidant level drops at oral phase, and then rises at gastric phase and lastly drops at intestinal phase for FRAP and DPPH assay. For ABTS assay, the antioxidant drops at oral phase and gastric phase then lastly rises at intestinal phase. In conclusion, heat inactivation will increase the antioxidant ability of the probiotic, hence it will also increase the antioxidant level when it is subjected to gastrointestinal digestion conditions.