Band 16, Heft 11

This study conducted a detailed evaluation of the nutritional value and proximate composition of milled quinoa grain at different dehulling rates with the goal of identifying a range of dehulling rates that retain the maximum level of nutrients and phytochemicals. Eleven samples of quinoa grain processed at different dehulling rates were obtained through light abrasive milling. The relationship between the dehulling rate and the nutritional composition of quinoa grain was determined. As the dehulling rate increased, the proportions of protein, fat, dietary fiber and ash decreased, whereas the proportion of starch increased. With the increase of dehulling rate, increasing amounts of protein, fat, starch, dietary fiber, saponin, flavonoids, and total phenolic were lost with the hull residue. At the dehulling rates of 8.6%, 11.72% protein, 7.57% fat, 4.72% starch, 28.9% total dietary fiber, 45.5% soluble dietary fiber, 48.58% saponin, 26.18% flavonoid, and 42.25% total phenolic were lost in dehulled quinoa grain compared with the raw quinoa grain. Optical microscope photos and scanning electron microscope (SEM) images showed that only the pericarp of quinoa was scoured when the dehulling rate was below 8.6%, and the quinoa grain retained a complete embryo. Therefore, to retain maximum nutritional and phytochemical content in the quinoa and maintain quinoa grain integrity, it is necessary to limit the dehulling rate of quinoa in the range of less than 8.6%.

Polyphenol oxidase (PPO) has been purified from the rosemary plant ( Rosmarinus officinalis L.) through three-phase partitioning (TPP) and has been biochemically characterized. The optimized TPP consisted of 50% ( w / v ) ammonium sulfate and equal volumes of crude extract and tert-butanol prepared at pH 6.5 and room temperature. Using this system, PPO was purified 14-fold, with 230% recovery of activity from the middle phase. The partitioned enzyme had a molecular mass of 53 kDa. The highest enzyme activity was detected at 30 °C and pH 7.0 against catechol. In substrate specificity tests, the enzyme displayed activity towards catechol, 4-methylcatechol, caffeic acid, hydroquinone, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), pyrogallol, syringaldezine, and 3,4-dihydroxy-L-phenylalanine but no activity towards L-tyrosine. The enzyme was inhibited by the common PPO inhibitors; salicylhydroxamic acid (SHAM), cetyltrimethylammonium bromide (CTAB), polyvinylpyrrolidone (PVP), and the organic solvent dimethyl sulfoxide (DMSO). Enzyme activity increased in the presence of the organic solvents acetone, ethanol, and methanol.

Refrigerated treatment offers an effective avenue to delay spoilage process of aquatic products during storage, while none or less study has been reported for bivalve species. This work aims to investigate the variations in different storage freshness of frozen razor clam samples, by which an effective evaluation system based on frozen kinetics models was established. In this study, fresh razor clam samples were preserved at the temperature of 268, 258, and 248 K for 40 days, respectively. The spoilage process was determined by a series of freshness assays, including sensory score (SS), electric conduction (EC), total volatile basic nitrogen (TVB-N), K -value, and total colonies counts (TCC). On this basis, the variations in these indexes were fitted by zero-, first- and second- order kinetic models. Results showed that zero -order kinetic model was more suitable to fit each freshness trend. Accordingly, the shelf life of razor clam was predicted as 47∼54, 79∼84, and 121∼154 days when the samples were preserved at 268, 258, and 248 K, respectively. This study revealed the general trends of the frozen decay process of bivalve species, which is instructive to establish applicative models for the real distribution chain.

Salmon skin collagen peptides (SSCPs) have potential for improving physiological conditions such as early alcoholic liver injury, type 2 diabetes and hypertension. Here, we focused on the in vitro effects of SSCPs on vascular function. For the production of SSCPs, alcalase and papain were used to hydrolyse the skin of Atlantic salmon ( Salmo salar L.), and their separation was made by reverse-phase high performance liquid chromatography. There were 10 low-molecular-weight peptides newly identified by mass spectrometry. In addition to five peptides previously identified, a total of 15 peptides were applied to an in vitro analysis of cholesterol-reducing, vasorelaxant and antithrombotic activities. The results showed that the SSCPs contained six cholesterol-lowering peptides (Ala-Pro, Leu-Gln, Asn-Val-Gly, Arg-Glu-Arg, Pro-His and Gly-Pro-Arg), two vasorelaxant peptides (Leu-Gln and Pro-His), and four antithrombotic peptides (Gly-Pro-Arg, Arg-Glu-Arg, Val-Asp-Gly-Lys and Val-Arg) as novel candidate peptides with beneficial effects on vascular function. These active peptides were also quantified. This study reveals that several peptides from salmon skin possess bifunctional properties.

In this study, the effect of the flour, which was obtained from stale bread, on flour and bread quality was investigated. The bread that was staled at refrigerator for 7 days was prepared as whole and crumb, and was grinded to convert into flour. The staled whole and crumb bread flours were stored at −18 °C and used to replace 0, 15, 30 and 45% of wheat flour. Then microbiological and physicochemical properties of flours; physical, textural and sensory properties of bread obtained from these composite flours were investigated. We concluded that stale bread flour could be used for bread production at the level of 15%. If the total bread production and consumption is considered, this addition level could provide a significant amount of waste bread recycling each year.

The aim of this study was to assess the inhibitory effect of three commercial bioprotectant agents on the growth of yogurt-spoiling fungi. Mucor circinelloides, Mucor racemosus, Penicillium spp., Saccharomyces exiguus, and Candida intermedia , commonly involved in the spoilage of dairy products, were isolated from spoiled yogurt and were fully characterized using molecular and phenotypic methods. HOLDBAC-YMC™ , Lyofast-FPR2™ and MicroGARD 200™ were used as antifungal products. An optimized experimental mixture design was applied to determine the proportion of each bioprotectant in terms of growth-inhibition response against the fungal strains in standard laboratory media. The results of the challenge tests showed that the application of bioprotectants inhibited the growth of the moulds in the range of 85–100% and the growth of yeast between 1.23 and 5.40 log cycles. The optimal combination of the bioprotectants was determined, tested in standard laboratory media and found to inhibit fungal growth. The antifungal effect of the optimal combination of the bioprotectants was validated in yogurt against the most resistant fungal species of the study, M. circinelloides and C. intermedia . The bioprotectants elicited antifungal effect in yogurt by completely inhibiting all of the tested fungi compared to controls. To the best of our knowledge, this is the first time a mixture of commercial bioprotectants has been tested on yogurt as a potential alternative for the biopreservation of yogurt in order to reduce spoilage of fermented dairy products and economic losses.

It was hypothesized that inhibition zone of an essential oil (EO) in a Petri dish might be relevant to its diffusion coefficient (DC) into agar medium, which may be calculated from the Fick’s diffusion. Antibacterial activities of cumin, dill weed, fennel, ginger and oregano EOs were evaluated against Campylobacter jejuni and Campylobacter coli . DCs, zeta potential and droplet sizes of EOs were measured. The inhibition zones of EOs had in accordance with DCs whereas they had a reverse relation with droplet size. The measured DCs were in the range of 0.82–1.50 × 10 −12  m 2  s −1 . The effective DC of EOs calculated from the total flux exhibited good correlations with measured DCs. Outcomes of this study may provide a pre-assessment for the antimicrobial activity of any EOs from its DC. Furthermore, it may help to understand the studies on how EOs pass through a bacterium cell and show antimicrobial effects.

Ultrasonic extraction was a new development method to achieve high-efficiency extraction of Lycium barbarum polysaccharides instead of hot water extraction. In this paper, the single factor method combined with the box Behnken design of response surface method was used to study the influence of extraction time, extraction temperature, material liquid ratio and ultrasonic power on the extraction rate of L . barbarum polysaccharide. The results indicated that the best extraction rate of L . barbarum polysaccharide was 12.54 ± 0.12% under the conditions of 80 min for extraction time, 73 °C for extraction temperature, 1 g:38 mL for material to liquid ratio, and 185 W for ultrasonic power. Under the same operating conditions, the yield of L . barbarum polysaccharide using ultrasonic extraction was 83.3%, which was higher than that hot water extraction. Moreover, the extraction time of ultrasonic extraction was only 47% of that using hot water extraction. This suggested that there was great potentials of using ultrasonic extraction in the realization of high-efficiency extraction of L. barbarum polysaccharide. The results of this study could also provide a theoretical basis for the coupling of ultrasonic extraction and ultrasonic concentration process to develop the integrated equipment of both ultrasonic extraction and ultrasonic concentration.