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Purple rice, locally known as "Cam" rice, is cultivated in the southern region of Vietnam. The bran of "Cam" rice is often disregarded and underutilized; nevertheless, it harbours substantial nutritive value, particularly in terms of antioxidant compounds. Additionally, sonication, an emerging and "green" technological approach, has been employed to augment the extraction efficiency of these antioxidants. This research is aimed at optimizing and maximizing the antioxidant recovery capacity including phenolic and total flavonoid compounds, along with their antioxidant activities, through the assistance of ultrasound waves. The effect of the extract on the starch digestion process was also investigated. The study employed the Box-Behnken experimental design, encompassing three variables: extraction time (20-40 minutes), temperature (60-80°C), and solvent-to-material ratio (8 : 1 to 12 : 1). Analysis was conducted on total phenolic compounds, total flavonoid content, and antioxidant activities. Results demonstrated that the peak yield of antioxidant compounds and their corresponding activities were attained at an extraction duration of 29.38 minutes, a temperature of 69°C, and a solvent-to-material ratio of 9.92. Under these optimal conditions, the yields were as follows: total phenolic compounds at 60.821 mg GAE/g, total flavonoid compounds at 3.2696 mg QE/g, percentage inhibition of DPPH at 74.778%, and FRAP value at 54.112 µmol Fe (II)/g. The established models were validated and exhibited a strong alignment between predicted and actual values, with disparities of less than 3% under optimal conditions. Furthermore, the extract was codigested with cooked corn starch, revealing a dose-dependent effect on starch digestibility. The sluggishness of digestion rate was observed when 20 mg of the extract was supplemented to 200 mg of cooked corn starch. This suggests that rice bran extract holds promise as an effective ingredient for mitigating starch digestion, particularly beneficial for individuals dealing with diabetes.

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Mulberry powder was created from the extract using a foam-mat drying process. The studies aimed to evaluate the effects of egg albumin, carboxymethyl cellulose (CMC), digestion-resistant maltodextrin (DRM) contents, and whipping time (5 to 15 min) on the foam properties. The impact of different drying temperatures (60 to 75 °C) on the quality of the finished mulberry powder was also noted. The best foam expansion/stability value was determined using multiple regression models as a function of egg albumin, CMC, DRM, and whipping time. The results indicated that the main influencing factors for the foam properties were whipping time followed by egg albumin, CMC, and DRM. Optimum values of foam expansion and stability were achieved at 467.9% and 97.02%, respectively. The foam had a porous structure and good stability for subsequent drying, with optimal contents of egg albumin, CMC, and DRM used at 7.6%, 0.4%, and 2%, respectively, along with a whipping time of 14.5 min. The established models had a high coefficient of determination (R2 > 0.9) and a high correlation between the predicted and observed values. Therefore, the model could be adjusted to determine the characteristics of the foam suitable for subsequent drying. The optimal values were then also verified. Minimal fluctuations (1.78−2.98%) between the experimental data and the optimal value were found. The drying temperature also significantly affected the quality of the mulberry powder. The foam was dried at 65 °C for 4 h to produce apowder with a beautiful light color (L* = 62.65), a characteristic purple-red color of mulberry (a* = 5.97). The moisture, water activity, and anthocyanin content of the finished mulberry powder were 4.57%, 0.3, and 5.4 mg/g, respectively.

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BACKGROUND: A statistical model was developed in this study to describe lactic acid production through a fermentation process of carrot in a rice bran bed by Lactobacillus plantarum. METHODS: Response surface methodology (RSM) based on Box-Behnken design was employed to statistically evaluate and optimize the conditions for maximum lactic acid production. RESULTS: The significance and interaction of salt concentration, water and initial L. plantarum starter density on final lactic acid content were found. With the use of the developed quadratic model equation, a maximum achieved lactic acid content of 1.35% was obtained in a rice bran bed fermentation process at optimum operating conditions of approximately 2.95% salt, 48.24% water and 2.9 log cfu/g of L. plantarum. After fermentation, the amount of total polyphenol content, antioxidant activity and carbohydrate had increased while the β-carotene in carrot was significantly retained (92.84%). CONCLUSIONS: The above results could provide a practical basis for the fermentation process in rice bran bed to produce a delicious and reliable product using L. plantarum strain XK 1.4 which could be a significant contribution to the food industry.

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Some physicochemical characteristics and bioactive compounds of three varieties of black cherry tomato (Indigo Rose, OG, F1:001) grown in Vietnam were investigated. The results showed that the two varieties OG and F1:001 have roughly the same size with weight, height, diameter, geometric diameter and surface area ranging from 21.62 to 22.25 g, 25.69 to 26.40 mm, 24.46 to 25.11 mm, 24.86 to 25.53 mm and 19.47 to 20.51 cm2, respectively. Meanwhile, the Indigo variety is twice as large with the corresponding parameters as 45.2 g, 48.03 mm, 55.18 mm, 52.69 mm and 87.20 cm2. All three varieties are in a spherical shape with sphericity and aspect ratios ranging from 96.72 to 109.69% and 0.951 to 1.149, respectively. The variety of OG contained higher levels of bioactive compounds, especially anthocyanin, not only in the skin but also in the outer tissue. Six anthocyanin compounds were identified in the two varieties of OG and Indigo Rose while only four anthocyanin compounds were found in the variety of F1:001. Among them, two new compounds (delphinidin-3-(p-coumaroyl)-glucoside and delphinidin-3-(p-coumaroyl)-glucoside-arabinoside) were discovered in all three varieties. The finding of this study will be a basis for consumers to better understand the nutritious properties of black cherry tomatoes grown in Vietnam, thereby promoting the need to grow and consume this beneficial fruit. The study also provides the important physicochemical parameters of black cherry tomatoes, which are the initial basis for fruit preservation and processing.

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Butterfly pea flower have great sensory attraction, but they have not yet been used widely in Vietnam. Extracts of butterfly pea flowers can be used conveniently as a natural blue colorant for food products. In this study, the identification of anthocyanin compounds in butterfly pea flowers was performed by UPLC coupled with a UV and Mass spectrometer instrument. Positive and negative ion electrospray MS/MS chromatograms and spectra of the anthocyanin compounds were determined. By analyzing the chromatograms and spectra for each ion, five anthocyanins were identified in the butterfly pea flower extract; these were delphinidin-3-(6″-p-coumaroyl)-rutinoside, cyanidin 3-(6″-p-coumaroyl)-rutinoside, delphinidin-3-(p-coumaroyl) glucose in both cis- and trans- isomers, cyanidin-3-(p-coumaroyl-glucoside) and delphinidin-3-pyranoside. Additionally, based on their intensity, it was determined that cyanidin-3-(p-coumaroyl-glucoside) was the most abundant anthocyanin, followed by cyanidin 3-(6″-p-coumaroyl)-rutinoside, delphinidin-3-(p-coumaroyl-glucoside), delphinidin-3-(6″-p-coumaroyl)-rutinoside and delphinidin-3-pyranoside. In this study, cyanidin derivatives were discovered in butterfly pea flower extract, where these compounds had not been detected in previous studies.

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A combination of freeze-dried powder of disproportionating enzyme (D-enzyme)-containing potato tuber and ß-amylase-containing ramie leaf was used to improve the gluten-free (GF) bread, and its physicochemical properties were characterized. The presence of D-enzyme and ß amylase in the potato tuber and ramie leaf was confirmed. Sixty five percent of partially gelatinized rice flour and 20% corn starch was combined with 10% freeze-dried potato tuber and 1% ramie leaf powder, and baked. The specific volume increased by 23% compared to the control with improved internal characteristics. Texture profile analysis revealed that retrogradation of the bread was retarded when stored for 90 h at 4 °C. The bread crumb amylose content was reduced from 14 to 9% and amylopectin branch chain-length distribution was rearranged, whereby the proportions of the branch chains with Degree of polymerization (DP) < 9 and DP > 19 decreased. The results suggest that D-enzyme and ß-amylase cooperatively altered amylose/amylopectin ratio and amylopectin structure.