This research aimed to evaluate the effects of thermal processing on the amino acid composition, molecular weight distribution (MW) and antioxidant activities of Jasmine rice bran protein hydrolysates (JBH). JBH was prepared by enzymatic hydrolysate (alcalase and flavourzyme at a ratio of 9.81:90.19, 2.84% w/w) for 60 min. JBH samples were treated as follows: non-heat (NJBH), pasteurisation (72°C, 15 min; PJBH) and sterilisation (121°C, 15 min; SJBH). For SJBH treatment, the browning index and fluorescence intensity increased (P < 0.05). FTIR showed that thermal process changed the intensities and location of some bands. Thermal processing affected MW by decreasing it from high MW (>10 kDa) to medium (3-10 kDa) and low MW (<3 kDa). Val, Met, Ile and Leu contents increased after thermal processing. Compared with NJBH, the IC 50 values of ABTS and FRAP of SJBH were not significantly different, while the IC 50 of DPPH increased (P ≥ 0.05).

This study aimed to optimize the hydrolysis conditions for producing jasmine rice bran protein hydrolysate (JBH) using response surface methodology (RSM). The independent variables were the ratio of flavourzyme to alcalase (Fl:Al; 0: 100 to 15: 85; 2.84% enzyme concentration) and hydrolysis time (60–540 min). The optimum hydrolysate was obtained at an Fl:Al ratio of 9.81: 90.19 for 60 min, since it enabled high amounts of protein, high antioxidant activity and more low molecular weight proteins. The experimental values obtained were a degree of hydrolysis (DH) of 7.18%, a protein content of 41.73%, an IC50 for DPPH of 6.59 mg/mL, an IC50 for ABTS of 0.99 mg/mL, FRAP of 724.81 mmol FeSO4/100 g, and 322.35 and 479.05 mAU*s for peptides with a molecular weight of < 3 and 3–5 kDa, respectively. Using a mixture of enzymes revealed the potential of mixed enzymes to produce JBH containing more small peptides and high antioxidant activity.

Background: Fishery industry has been important for Thai’s economic more than 30 years. It leads Thailand to be the one of world’s largest canned tuna producer and exporter. However, mainly white meat part is used in canned tuna product while the waste comprises roe, viscera, head and dark meat is sold to feed meal plant or sold as cheap material even its nutritive value is still high. There is well know that sea fish as tuna is a good source of polyunsaturated fatty acid (PUFA) such as Eicosapentaenoic acid (EPA) and Docosahexanoic acid (DHA). Many people around the world play more attention with salad dish with the dressing. Generally, mayonnaise is prefer for the salad dressing and it normally consists of chicken egg yolk which high saturated fatty acid and in addition, fat content in mayonnaise normally is about 30-65%. Therefore, normal mayonnaise is high in fat content and low polyunsaturated fatty acid then consuming this product may not a great idea for on diet or controlled weight people.Objective: To increase omega-3 by tuna roe substitution and to replace fat content by using inulin gel.Methods: Tuna roe was prepared by soaking with galangal extracted with 95% ethanol for removal fishy/rancidity odor. Inulin powder 45 g was added in to water to obtain final suspension 100 ml before brought to heat at temperature 65oC for 15 min to form a gel and stored at 4oC. Omega-3 mayonnaise product was started with using 100% tuna roe substitution for egg yolk. Thereafter, inulin gel was added to replace vegetable oil at 0, 25, 50, 75 and 100%. Basic mayonnaise containing egg yolk and 0% inulin gel (100% soy bean oil) was used as control sample. Color and emulsion stability test were monitored for physical quality. pH value, peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) were used for chemical quality. Total viable count (TVC), yeast and mold, lactic acid bacteria (LAB) and coliform were measured for microbiological quality. Sensory evaluation using 9-point hedonic scale technique was also monitored.Results: When increased inulin gel into the mayonnaise, L* value significantly increased while a* and b* values significantly decreased (p<0.05). Without added inulin gel, mayonnaise producing by using tuna roe had lower emulsion stability test (%) compared with control sample using egg yolk. It was found that using inulin gel significantly increased moisture contents and water activity of mayonnaise. However, there was no significantly different found in pH value in any sample. In addition, tuna roe mayonnaise with and without added inulin gel possessed higher lipid oxidation products determined as PV and TBARS value compared with basic mayonnaise using egg yolk. All microbiological quality indices were very low and passed standard regulation of mayonnaise product. Though, consumer acceptability of mayonnaise producing from tuna roe was lower than that of control, 50% of inulin gel substitution seemed to have better sensory score when compared with other inulin gel substitution groups. Therefore, sensory improvement of omega-3 mayonnaise product substituted with inulin gel need to be further studied.Conclusions: Mayonnaise producing from tuna roe and replacing fat with inulin gel between 25 to 100% were successful when determined by emulsion stability, pH value and microbiological quality. However, sensory score of using 100% tuna roe with and without inulin gel substitution for making mayonnaise was lower than that of control. Among tuna roe mayonnaise substituted with inulin gel, 50% should be selected for sensory improvement in the further work.Keywords: Tuna roe, Mayonnaise, Inulin, Omega-3

The objective of this research was to investigate the effects of pulse electric field, microwave, and ultrasonic assisted water extractions on the bioactive compounds in black rice, and their antioxidant and sirtuin1 enzyme stimulating activities. The number of pulses were changed from 1,000 to 2,000 and 3,000 at a constant electric field intensity of 5 kV/cm. Microwave and ultrasonic conditions were followed by 800 W for 20 min and 60 °C for 20 min, respectively. The results found that using pulse electric field with 3,000 pulses and microwave achieved high concentrations of total phenolic compound and cyanidin-3-glucoside with non-significantly difference. Extracts from the pulse electric field with 3,000 pulses showed the significantly highest DPPH scavenging activity (30.83 ± 2.06%) and the sirtuin1 enzyme stimulating activity (27.260 ± 0.418 of fluorescence intensity) when compared with microwave and ultrasonic extractions. Scanning electron microscopy and fourier transform infrared spectroscopy results showed distinct differences between the effects of these methods on the outer surface. The overall results revealed that pulse electric field and microwave were similarly effective at increasing the content of bioactive compounds in extract and their antioxidant activities. However, the pulse electric field was considerably more effective for activating sirtuin1 enzyme activity.

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