Impact of processing technologies on isoflavones, phenolic acids, and antioxidant capacities of soymilk prepared from 15 soybean varieties.

In the present study, soymilk samples were prepared from 15 soybean varieties by employing dry method-raw slurry filtration (D-BAF), dry method-cooked slurry filtration (D-BBF), wet method-raw slurry filtration (W-BAF), and wet method-cooked slurry filtration (W-BBF). Different varieties of soybean and processing techniques were found to impose a significant impact on total phenolics, total flavonoids, phenolic acids, isoflavones and antioxidant capacity of soymilk samples. Overall, the soymilk prepared by W-BAF exhibited a higher level of total phenolic content and antioxidant activity. The soymilk samples prepared by W-BBF presented higher values for total flavonoid content and ferric-reducing antioxidant power assay. The soymilk prepared by W-BBF presented higher subtotal values of phenolic acids. In comparison, the soymilk prepared by D-BAF exhibited high amount of total isoflavones followed by the soymilk processed by W-BAF. Overall, the wet method was found to be responsible for improved phenolic contents and antioxidant activity of soymilk sample.

Yu X ，Meenu M ，Xu B ，Yu H ... -  《-》

Isoflavones, Flavan-3-ols, phenolic acids, total phenolic profiles, and antioxidant capacities of soy milk as affected by ultrahigh-temperature and traditional processing methods.

Xu B ，Chang SK 《-》

Innovative Soaking and Grinding Methods and Cooking Affect the Retention of Isoflavones, Antioxidant and Antiproliferative Properties in Soymilk Prepared from Black Soybean.

This study's objective was to characterize the effect of traditional and 3 newly devised (soaking+grinding) methods combined with cooking on the content and composition of phenolic substances, antioxidant, and antiproliferative properties of soymilk prepared from black soybean. Phenolic substances and antioxidant profile were characterized and antiproliferation of prostate cancer DU145 cells was conducted using a cell culture assay. Results indicated Grinding Method 4 produced significantly (P < 0.05) higher total phenolic content (TPC), total flavonoid content (TFC), condensed tannin content (CTC), and total isoflavone content in both raw and cooked black soymilk as compared to Method 1. Cooking soymilk reduced 23% to 38% of total phenolic substances. Raw black soymilk produced by Method 4 displayed the highest antioxidant capability, which was determined using ORAC, FRAP, and DPPH assays, and a higher antiprostate cell proliferation ability. Cooking only slightly reduced the potency to inhibit DU145 prostate cancer cells as IC50 value was increased from the average of about 4.0 mg/mL of raw soymilk extracts to 5.5 mg/mL of cooked soymilk extracts of all grinding methods. Overall, total isoflavone content was the only component that was negatively correlated with IC50 value (r = -0.93, P < 0.05) which indicates the ability to inhibit prostate cancer cell is associated with the increase in total isoflavone content, not with any other phenolic substances or antioxidant properties.

Tan Y ，Chang SK ，Zhang Y 《-》

Effect of Cooking on Isoflavones, Phenolic Acids, and Antioxidant Activity in Sprouts of Prosoy Soybean (Glycine max).

Soy sprouts possess health benefits and is required to be cooked before consumption. The effects of cooking on the phenolic components and antioxidant properties of soy sprouts with different germination days were investigated. A food-grade cultivar Prosoy with a high protein content was germinated for 1, 2, 3, 5, and 7 d and cooked till palatable for 20, 20, 5, 5, and 7 min, respectively. Total phenolic content (TPC), total flavonoids content (TFC), condensed tannins content (CTC), individual phenolic acids, isoflavones, DPPH, ferric-reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC) of raw and cooked sprouts were measured. Cooking caused significant losses in phenolic content and antioxidant activities, and maximum loss was on day 3 > 5 > 7, including TPC (32%, 23%, and 15%), TFC (50%, 44%, and 20%), CTC (73%, 47%, and 12%), DPPH (31%, 15%, and 5%), FRAP (34%, 25%, and 1%), and ORAC (34%, 22%, 32%), respectively. Cooking caused significant losses in most individual phenolic acid, benzoic group, cinnamic group, total phenolic composition, individual isoflavones, and total isoflavones. The losses of phenolic acids such as gallic, protocatechuic, hydroxybenzoic, syringic, chlorogenic, or sinapic acids during cooking were not compensated by the increases in trihydroxybenzoic, vanillic or coumaric acids on certain days of germination. Cooking caused minimal changes in phenolic acid composition of day 1 and 2 sprouts compared to 3, 5, and 7 d sprouts.

Kumari S ，Chang SK 《-》

Soymilk processing with higher isoflavone aglycone content.

The objective of this work was to optimise conversion of β-glucoside isoflavones to aglycones in soymilk processing and to evaluate their thermal stability. The soymilk was assessed for time and temperature effects of incubating supplied to central composite design 2(2). The response functions were investigated for β-glucosidase activity and isoflavone contents. The β-glucosidase activity was reduced through soybean slurry incubation at approximately 64°C and 3.42h. Maximum conversion of β-glucosides into isoflavone aglycones involved soaking the soybeans at 5°C for 14h at a 1:3 ratio (soybean:water, w:v), homogenising them at a 1:8 ratio (soybean soaked:water, w:v) and incubation at 50°C for 2.7h. In evaluation of thermal stability of isoflavones in soymilk at 97°C for 25min, the daidzein and genistein aglycone contents were maintained, the glycitein and β-glucosides contents increased and the malonylglucoside content decreased.

Baú TR ，Ida EI 《-》