Substitution Effect of Enzymatically Hydrolyzed Purple Sweet Potato Powder on Skim Milk in Yogurt Preparation

Abstract

Yogurt was prepared with different substitution ratio [10, 30, and 50% (w/w)] of skim milk with enzymatically hydrolyzed purple sweet potato powder (EHPSPP) and fermented at 40 o C for 15 h. Fermentation characteristics and antioxidant activities of the yogurt were evaluated in terms of acid production (pH and titratable acidity) and lactic acid bacterial counts and DPPH radical scavenging activity, respectively. After 15 h fermentation, titratable acidity of EHPSPP yogurt was 0.80−0.89% and was lower than that (0.93%) of yogurt made without EHPSPP. The acid production and the number of viable lactic acid bacterial cell decreased with increasing the substitution ratio. The sensory score of EHPSPP yogurt prepared with 30% substitution ratio showed the highest values in taste and overall acceptability among the tested yogurt preparations. DPPH radical scavenging activity increased with increasing the substitution ratio in yogurt fermented for 12 h. The total phenolic content of 30% EHPSPP yogurt was 40% higher than that of skim milk yogurt. These results suggest that EHPSPP can be used as substituent of skim milk and the optimum substitution ratio is around 30%.

Fermentation and Quality Characteristics of Yogurt Treated with Bifidobacterium longum

“…As the B. longum inoculum concentration increased, the reducing sugar content decreased. The group inoculated with 0.0015% of B. longum displayed an increase from 44.12 mg/mL before fermentation to 50.19 mg/mL after 4 h of fermentation and decreased to 46.97 mg/mL after 8 h of fermentation, and these results were similar to those reported in a study by Kim et al [13]. As fermentation proceeds, sugar is converted to acid and its content decreases.…”

“…The lactose content of yogurt was analyzed by modifying the method described by Kim et al [13]. Subsequently, 49 mL of 70% acetonitrile was added to 1 mL of the sample, diluted 50 times, filtered through a 0.2 µm membrane filter, and analyzed using HPLC (Jasco System, Tokyo, Japan).…”

Effect of enzymatically hydrolyzed potato powder on quality characteristics of stirred yogurt during cold storage

“…Previously, yogurt and flavored cheese were prepared with enzymatically hydrolyzed sweet purple PP and black pepper powder, respectively (Kim et al, 2015;Rahimi et al, 2020). However, there is no report available that reveals the effect of enzymatically hydrolyzed potato powder (EHPP) with whole milk powder (WMP) on the physicochemical properties of yogurt and its storage stability.…”

Phytochemical component and toxicological evaluation of purple sweet potato leaf extract in male Sprague–Dawley rats

“…A recent study showed that PSPL is a strong antioxidant with radical scavenging ability due to the presence of natural bioactive compounds such as anthocyanin ( Yuzhi Jiao Studies on antioxidant, 2012 ). Due to its natural essences, PSPL has been formulated into a probiotic to make its consumption easier and so that more people can experience the maximum benefits ( Kim et al, 2015 ). Some of the other identified minerals in PSPL include sodium, potassium, calcium, magnesium, iron, copper, manganese, and zinc ( Sun et al, 2014 ).…”