Totally found 68 items.

  • [期刊] Comparison of microwave and high-pressure processing on bound phenolic composition and antioxidant activities of sorghum hull
    The influence of microwave boiling (MB treated 5, 10 and 15 s was abbreviated as MB5, MB10 and MB15, respectively) and high-pressure boiling (HB processed 10, 20 and 30 min was denoted as HB10, HB20 and HB30, respectively) processing on the composition and content of bound phenolic substances of sorghum hull and their antioxidant capacity were evaluated. Nine bound phenolic profiles were identified by HPLC-ESI-MS/MS, including syringic acid, veratric acid, p-hydroxybenzonic acid, caffeic acid, sinapic alcohol, ascorbic acid, prenylnaringenin and luteolin. Compared with traditional hot water processing (HP treated 10, 30 and 50 min was abbreviated as HP10, HP30 and HP50, respectively), the content of free procyanidins and total phenolics of sorghum hull treated with HB increased by 35.92-58.87% and 6.20-18.70%, respectively. Sorghum hull treated with HB20 possessed the highest ABTS (ABTS radical scavenging capacity) and FRAP (ferric ion reducing antioxidant power) among all treatment groups.
  • [期刊] Effect of synthetic microbial community on nutraceutical and sensory qualities of kombucha
    To mass-produce nutritional kombucha with quality consistency, it is necessary to design synthetic microbial community (SMC) starters with clear bacterial compositions. In this study, a three-species SMC, including Acetobacter pasteurianus, Gluconacetobacter xylinus and Zygosaccharomyces bailii, was designed. Acetic acid bacteria (AAB) in SMC produced a higher concentration of organic acids synergistically compared to each strain inoculated alone. Gluconic acid was the most abundant organic acid in kombucha fermented by SMC, which contributed to the pleasant sour taste of the beverage. AAB could also oxidise the alcohol produced by Z. bailii, making kombucha a soft beverage. Total phenol and flavonoid concentrations increased during fermentation, which enhanced the health benefits of kombucha. The sensory evaluation demonstrated tsshat sensory attributes of SMC fermented kombucha were quite similar to those fermented by the symbiotic culture of bacteria and yeast (SCOBY). Therefore, SMC could be utilised in the industrial mass production of kombucha for better quality control and product consistency.
  • [期刊] Effect of synthetic microbial community on nutraceutical and sensory qualities of kombucha
    To mass-produce nutritional kombucha with quality consistency, it is necessary to design synthetic microbial community (SMC) starters with clear bacterial compositions. In this study, a three-species SMC, including Acetobacter pasteurianus, Gluconacetobacter xylinus and Zygosaccharomyces bailii, was designed. Acetic acid bacteria (AAB) in SMC produced a higher concentration of organic acids synergistically compared to each strain inoculated alone. Gluconic acid was the most abundant organic acid in kombucha fermented by SMC, which contributed to the pleasant sour taste of the beverage. AAB could also oxidise the alcohol produced by Z. bailii, making kombucha a soft beverage. Total phenol and flavonoid concentrations increased during fermentation, which enhanced the health benefits of kombucha. The sensory evaluation demonstrated tsshat sensory attributes of SMC fermented kombucha were quite similar to those fermented by the symbiotic culture of bacteria and yeast (SCOBY). Therefore, SMC could be utilised in the industrial mass production of kombucha for better quality control and product consistency.
  • [期刊] Hot air drying of tea flowers: effect of experimental temperatures on drying kinetics, bioactive compounds and quality attributes
    The drying process is important for the quality and value of tea flower products. In the present work, the effects of different hot air drying (HAD) temperatures from 60 to 120 degrees C on drying kinetics, bioactive compounds (catechins, flavonol glycosides and triterpenoid saponins) and quality attributes (volatile compounds, colours and antioxidant properties) of tea flowers were systematically evaluated. The results showed that higher drying temperature resulted in a shorter drying time but with greater loss of bioactive compounds and quality attributes. Flowers subjected to HAD at 60 degrees C showed the highest bioactive contents and quality attributes of all HAD samples and the quality of HAD 60 degrees C samples were close to that of freeze-dried samples. Taking account of the production efficiency and energy consumption, the tea flowers dried at 60 degrees C for 180 min was preferred. These findings provide a guide for the processing of tea flowers with the aim of improving the overall quality of the product.
  • [期刊] Effects of particle size on physiochemical and in vitro digestion properties of durum wheat bran
    In order to promote the potential health benefits of high fibre products, wheat bran is the main focus of the food industry. The physiochemical and in vitro digestion properties of wheat bran containing different particle size were investigated and compared against raw bran samples. Firstly, the bran sample containing superfine particles (11.63 mu m) was hydrolyzed by the alpha-amylase, pepsin, and pancreatin enzymes separately using a single factor and orthogonal test. Secondly, optimized hydrolysis parameters of superfine particles were employed to measure in vitro digestibility of macronutrients in raw, coarse, medium, and superfine bran particles. The maximum degree of hydrolysis obtained via alpha-Amylase (concentration 10 mg mL(-1), pH 6.6, and time 12.5 min) was 55.71%; pepsin (concentration 50 mg mL(-1), pH 1.2, and time 9 h) was 82.10%; and pancreatin (concentration 100 mg mL(-1), pH 7.0 and time 12 h) was 84.71%, respectively. The highest in vitro digestibility rate of reducing sugar, protein, fat, and soluble fibre content was observed in superfine bran samples to 33.4%, 82.55%, 91.53%, and 21.66%, respectively.
  • [期刊] Effect of homogenisation on detection of milk protein content based on NIR diffuse reflectance spectroscopy
    Investigating the effect of homogenisation on the prediction performance of protein content by using near-infrared (NIR) spectroscopy is helpful to improve protein determination precision. For this purpose, the influence of homogenisation on milk fat globules and NIR spectra was analysed firstly. Then, NIR spectra of eighty-seven cow milk samples before and after homogenisation were obtained. Multiplicative scatter correction was used to do spectral pretreatment. Uninformative variable elimination based on partial least squares (UVE-PLS) and successive projection algorithm was used to extract characteristic variables. Partial least squares regression (PLSR) and least squares support vector machine models were established. The results showed that homogenisation made milk fat globules be distributed evenly, decreased the size of fat globules and improved NIR spectral repeatability and prediction precision on protein content. The best model was PLSR-UVE-PLS, having good and excellent protein prediction ability for un-homogenised milk (RMSEP = 0.06 g/100 g, RPD = 2.69) and homogenised milk (RMSEP = 0.04 g/100 g, RPD = 3.59), respectively.
  • [期刊] Purification of peptide fraction with antioxidant activity from Moringa oleifera leaf hydrolysate and protective effect of its in vitro gastrointestinal digest on oxidatively damaged erythrocytes
    Moringa oleifera leaf (MOL) is an excellent source of high-quality plant protein. MOL hydrolysate (MOLH) was prepared by enzymatic hydrolysis and ethanol precipitation. The adsorption kinetics of SP-207 resin for antioxidant peptides from MOLH were studied. The adsorption process for antioxidant peptides on SP-207 was well described by the pseudo-second-order kinetics model. The adsorption was a multi-molecule layer adsorption process, which was exothermic. The peptide fraction with antioxidant activity (MOLP, 40% ethanol elution fraction) possessing high contents of antioxidant and hydrophobic amino acids was obtained by SP-207 column chromatography. A total of eight dipeptides including PR, L(I)K, L(I)H, L(I)P, L(I)L(I), GE, VL(I) and PF were identified in gastrointestinal digest of MOLP by UPLC-QTOF-MS/MS. The protective effects of MOLP digest and LH on oxidatively damaged erythrocytes by inhibition of MDA formation were comparable to that of GSH, indicating that MOLP could be used as an antioxidative ingredient in functional food.
  • [期刊] UHPLC-ESI-QTOF-MS phenolic profiling and antioxidant capacity of bee pollen from different botanical origin
    In this work, bee pollen samples from different botanical origin were investigated for antioxidant capacity. Thereafter, a phenolic profiling was produced through a mass spectrometric untargeted metabolomic approach. Marked differences were identified in TPC, ranging from 4.2 (Magnolia) to 29.6 mg g(-1) GAE (Lamium). Wide differences were also recorded in antioxidant capacity (ORAC, ABTS and DPPH assays). Untargeted profiling allowed annotating 467 compounds with flavonoids being the most frequent class of phenolics followed by phenolic acids, tyrosols, lignans and other. OPLS-DA clearly discriminated the most represented floral families (Umbelliferae, Rosaceae and Fabaceae), suggesting, thus, that botanical origin leaves a characteristic phenolic signature in pollen. Overall, 35 phenolics accounted for most of the discrimination, with flavonoids being the most represented class. Despite the fact that further research is needed, the phenolic profile of bee pollen is a promising tool to investigate the botanical origin.
  • [期刊] Effects of different solvents on total phenolic and total anthocyanin contents of Clitoria ternatea L. petal and their anti-cholesterol oxidation capabilities
    Clitoria ternatea (CT) petals have a high content of polyphenolic compounds, including anthocyanins, which protect against lipid oxidation. This research evaluated total phenolic content, total anthocyanin content and antioxidant activity of CT extracts obtained using distilled water, methanol, and/or water-methanol combination (1:1) solvents after 6, 12 and 24 h soaking times. The predominant bioactive compounds of CT petals were kaempferol 3-neohesperidoside (462.63 mg per 100 g), caffeoylmalic acid (137.59 mg per 100 g), and kaempferol 3-(2G-rhamnosylrutinoside) (129.28 mg per 100 g). The capacity of each solvent-type extract obtained from 6 h soaking time to inhibit cholesterol oxidation was determined after 24 and 48 h in an emulsion model. At 6 h soaking time, the combination-solvent yielded an extract with the highest anthocyanin content (63.9 mu g mL(-1)) and inhibited 89.8% of 7-ketocholesterol production in emulsion, compared to the control. This study demonstrated that CT petal extracts can enhance health benefits and lengthen shelf life of emulsion-type products.
  • [期刊] Discolouration of raw and cooked coloured fleshed potatoes differing in anthocyanins and polyphenols content
    Despite variations in the content of polyphenols, the tested potato varieties with red and purple flesh contained similar amounts of anthocyanins. Potatoes of the red-fleshed HBr variety were distinguished by a significant content of pelargonidin-3-feruloylrutinoside-5-glucoside, and those of the purple-fleshed Vitelotte variety were characterised by a significant cyanidin-3-rutinoside content. Immediately after cutting, raw potatoes with red flesh showed a small share of yellow (b* parameter) and double the share of red (a*) as compared to purple-fleshed tubers. A reduction in the share of red dye was observed in purple- and red-fleshed potatoes except Vitelotte and Rosalinde tubers, at both 1 and 4 h after being cut. The flesh colour of cooked potatoes was characterised by low susceptibility to darkening, and purple-fleshed tubers were more saturated by chroma than tubers of red-fleshed varieties.
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