Studies on Producing Yeast Autolysate and its Antioxidant Properties to Enhance Flesh Apple Juice Qualities | ||||
| Journal of Food and Dairy Sciences | ||||
| Article 6, Volume 10, Issue 4, April 2019, Page 115-123 PDF (1.04 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jfds.2019.36186 | ||||
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| Authors | ||||
| E. A. Aboulnaga; Faten Y. Ibrahim | ||||
| Food Industries Department, Faculty of Agriculture, Mansoura University, 35516 Mansoura, Egypt | ||||
| Abstract | ||||
| Yeast (Saccharomyces cerevisiae) has an important role in food industries and it also considers as a powerful probiotic microorganism due to its high content of bioactive compounds. Therefore, we use it as food additives in the form of fresh, dry active, or inactive extract, while these additions to some foods is sensory unacceptable. This problem may be overcome by using yeast autolysate which contains most of the soluble bioactive compounds of the cells. Therefore, yeast autolysate was produced in the current study and the effect of growth phases on its bioactive compounds formation was investigated. The data revealed that, cells had diauxic growth phase and the highest reducing power (RP) and DPPH scavenging activity were obtained after the first exponential phase (cultivation time of 24 hr), however the maximum production of total antioxidant (TAC) and glutathione content (GSH) were observed at the end of the second exponential phase (after 60 hr cultivation). Additionally, thermal treatment of yeast autolysate at 40°C up to 30 min exhibited almost no effect on the bioactive compounds activity. While, the autolysate treatment with ≥ 60°C led to sharply decrease of TAC (40% less than control) and a little decrease of GSH, DPPH, and RP contents. A comparison analysis between yeast autolysate and flesh apple juice found that, the IC50 of yeast autolysate was 5.6 mg while it was 20 mg for flesh apple juice. Also, yeast autolysate had 53, 6.11, and 2.73-fold higher for GSH, TAC, and RP, respectively, compared with flesh apple juice. Addition of 0.02% thermally treated (at 40°C for 5 or 10 min) yeast autolysate to flesh apple juice was decreased browning index (BI) and hydroxymethylfurfural (HMF) to 12 and 18%, respectively, this decrease reached 25 and 40% for BI and HMF, respectively, when the addition level was 0.08% which also was sensory accepted. So, it could be concluded that, addition of yeast autolysate into flesh apple juice is sensory accepted, enhanced its antioxidant properties, and decreased enzymatic as well as nonenzymatic browning. | ||||
| Keywords | ||||
| Yeast autolysate– Antioxidant– thermal treatment– Flesh apple juice – Browning– Sensory evaluation | ||||
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