查看更多>>摘要：The aim of this study was to determine the changes in freezing-induced egg yolk gelation behaviour and mechanism. The rheological properties, particle size, moisture distribution, and structural characteristics of egg yolk during freezing were studied. The results showed that freezing increased the viscosity of the egg yolks. The k value, G ' and G '' all increased significantly, while the n value and tan delta decreased significantly, indicating that the egg yolk changed from liquid to solid form during freezing, and gelation occurred. Secondly, with the freezing time increased to 12 h, the average particle size of egg yolk increased from 29.42 mu m to 88.16 mu m, the immobile water increased from 62% to 67%, and the free water decreased from 37% to 32%. The increase of lambda max in the fluorescence spectrum and the ultraviolet spectrum revealed that the exposure of tyrosine residues on the protein surface increased and the conformation of the protein changed. As observed with confocal laser scanning microscopy (CLSM), freezing destroyed the protein structure, released lipids, and promoted egg yolk protein aggregation. Freezing-induced protein molecule interactions are a key factor in frozen-thawed egg yolk gel formation.
查看更多>>摘要：Whey protein-based nanocomplexes were fabricated to improve the stability and bioavailability of marine carotenoid-fucoxanthin (FX) by using whey protein isolate (WPI) as the core and Ca2+ crosslinked flaxseed gum (FG) as the shell. The results of multi-spectroscopic methods indicated that the incorporation of FX and FG changed the structural characteristics of WPI. FX could quench the intrinsic fluorescence of WPI by a static mechanism, indicating that they could spontaneously form a nanocomplex through non-covalent interactions. FX-WPI-FG-Ca nanocomplex with a nano scale (similar to 350 nm) was found to perform the best with the highest encapsulation efficiency (EE, 96.19 +/- 0.33%) and loading capacity (LC, 2.47 +/- 0.04%) and improved FX stability against ultraviolet B (UVB), heat, NaCl and pH. In addition, the nanocomplex was shown to effectively deliver FX into PC12, and cytotoxicity increased with the concentration. The encapsulated-FX perturbed lipid metabolism, causing ROS accumulation, mitochondrial damage and regulated apoptosis. In conclusion, the nanocomplexes assembled from WPI and FG may be effective encapsulation systems for FX, which could potentially become a new dietary supplement for cancer patients.
查看更多>>摘要：To study the phenolics in grains of hulless barley varieties harvested in the Qinghai-Tibet plateau region, free, esterified, and insoluble-bound phenolic fractions were extracted from grain of fourteen varieties. The phenolic components and antioxidant activity of the fractions were studied. Identification of phenolics profile in QB35 variety was studied using ultra-high-performance liquid chromatography-diode array with quadrupole time-of flight and tandem mass spectrometry (UPLC-QTOF-MS/MS), which revealed fourteen phenolics in the free form, four in the esterified form, and seventeen in the insoluble-bound form. Total phenolic contents (TPC) of the fractions were tested finding significantly (p < 0.05) higher phenolics content and greater antioxidant capacity (via DPPH and ABTS free radical scavenging assays) in insoluble-bound fraction than that of free and esterified fractions for the same hulless barley variety. In terms of phenolic components, ferulic acid was the dominant phenolic in all varieties. Chrysoeriol-7-O-glucuronide and chrysoeriol were identified and quantified in hulless barley varieties for the first time. This study also showed TPC, ferulic acid and luteolin significantly contributed to the antioxidant activities (p < 0.01). The fourteen hulless barley varieties could be classified depending on the geographical locations and the color of their grains via hierarchical cluster analysis (HCA). This study provides valuable new insights into the phenolics in grains of hulless barley varieties and their antioxidant potentials.
Arteaga, HubertRobleto-Martinez, EduardoSilva, Ana Carolina de SousaSouto, Sergio...
9页
查看更多>>摘要：The bioelectrical impedance, cell granulometry and the color of the freeze-thawed blueberries were investigated. The blueberries were subjected to freezing at -18 degrees C for 135 min, during this process, groups were removed to every 9 min, and stored at 4 degrees C until further analysis. Bioelectrical impedance, color, pH, total soluble solids and cell granulometry were measured. The characteristics of bioelectrical impedance, cell granulometry and color were analyzed by computational algorithms, which allowed extracting characteristic of blueberries during the freezing process. The results showed progressive loss of the cellular structure during freezing, this behavior was associated with the bioimpedance parameters. The cells damage also influenced color parameters, and cell granulometry. The color followed the direction toward darkness and more intense red-blue tones, which suggest the migration of pigments from the blueberry's skin towards the flesh. In conclusion, evaluation of the color and cell granulometry by computational algorithms with bioelectrical impedance provides a powerful tool for evaluating cell damage in blueberries during the freezing process.
查看更多>>摘要：The goal of this work was to investigate the use of selected starter cultures to obtain a spelt-based sourdough bread with improved technological, sensory and shelf-life characteristics. Two consortia were set up, containing a yeast strain (either a commercial Saccharomyces cerevisiae strain or a maltose-negative Kazachstania unispora strain) and two strains of Lactic Acid Bacteria (LAB), belonging to Weissella cibaria and Pediococcus pentosaceus species. The ability to grow in co-culture was investigated, and no inhibitions were recorded between the LAB and yeasts, that grew in proportions deemed desirable for sourdoughs. The performance of the two consortia was assessed in a spelt-based sourdough bread, and the leavening behavior, bread volume and crumb softness, shelf life and consumer preference were assessed. The product obtained with the consortium containing S. cerevisiae had superior crumb texture that was maintained through 5 d of storage, and was well accepted by the consumers. Furthermore, both consortia improved the mold free shelf-life when challenged with common cereal contaminants. The data showed that selected starter cultures have a good potential in improving the quality of bakery products obtained with flours that have a poor technological performance, such as spelt, but interesting nutritional properties and sustainable cultivation.
查看更多>>摘要：This study investigated the mass transfer process, penetration of seasoning, texture and sensory quality of pickled lotus root slices with pulsed electric field (PEF) pretreatment and corresponding mechanisms. Samples were subjected to 10,000 pulses in 20s (0.5, 1.0 and 1.5 kV/cm), blanched in boiling water and then soaked in brine (3% dark soy sauce and 15% NaCl). PEF pretreatment significantly enhanced water loss and NaCl gain throughout the pickling process, and higher effective diffusion coefficient (De) of PEF-pretreated samples (PEF = 17.42 and Control = 9.51, 10(-7) m(2)/s) resulted in a shorter period to approach the theorical osmotic equilibrium of NaCl (0.12 w/w). Furthermore, better appearance, flavor and pickled degree of samples were also attributed to PEF pretreatment. The acquired results revealed that PEF can be used to pretreat foodstuffs before pickling processing considering its effects on improving mass transfer and potential for cost reduction.
查看更多>>摘要：This study aimed to investigate the effect of low intensity of high pressure processing (LHP) on bioactive compound content and the antioxidant capacity of persimmon before digestion and during simulated in vitro gastrointestinal digestion (IVD). The astringent and non-astringent persimmon cultivars treated with LHP at 100 MPa for 10 min were analyzed for polyphenols, antioxidant activities and bioaccessibility. The results showed that LHP treatment significantly increased (P < 0.05) the extractability of polyphenols and antioxidant activities of non-astringent persimmon by 1.5-2.0 folds as compared to the non-treated control treatment. Additionally, LHP exhibited positive results for non-astringent cultivar as indicated by the higher recovery of polyphenols (204-279%), bioaccessibility index (192-205%) and residual antioxidant activities (44-399%) in comparison to the control after IVD. However, LHP treatment did not affect astringent cultivar. These findings suggest that the LHP could be applied to enhance nutritional property of non-astringent persimmon and may be used for developing novel health products with high functional bioactive compounds which tolerate the digestion system.
Dantas, AdrianaVerruck, SilvaniCanella, Maria Helena MachadoMaran, Bruna Marchesan...
11页
查看更多>>摘要：Lactose-free probiotic powders were obtained by mixing Bifidobacterium BB-12 suspensions with lactose-free milk powder or lactose-free milk powder and prebiotics (inulin or oligofructose). A thorough investigation was performed to know their water sorption properties and physical and thermal characteristics. By evaluating the water sorption properties, the Peleg model fitted well to the experimental sorption data, showing that the equilibrium moisture content of powders increased as the relative humidity increased. The isotherm found for all samples was a Type III Isotherm, commonly observed in most foods. For both morphology and particle size, the use of different carrier agents affected these properties; however, all the spray-dried powders presented good size to be added in food products. X-ray diffraction and Raman spectroscopy showed us amorphous structure for all powders, and typical bands of the milk constituents and sugars, respectively. Regarding the spray-dried powders thermal properties, it was possible to confirm that the addition of prebiotics gave higher thermal stability, highlighting the sample produced with inulin. We concluded that a good quality of lactose-free milk based probiotic powder could be obtained using spray drying technique, with great potential to be applied in lactose free dairy products.
Gungor, CandanBarel, MukaddesDishan, AdaletDisli, H. Burak...
7页
查看更多>>摘要：This study was designed to determine the prevalence of Methicillin Susceptible S. aureus (MSSA) and MethicillinResistant S. aureus (MRSA) and their source of contamination in the pastirma production chain. Additionally, this study was focused on the antimicrobial resistance, virulence profiles, biofilm-forming capabilities and phylogenetic relationships of obtained isolates. A total of 400 samples were analyzed and from which 105 (26.25%) were found positive for coagulase-positive with Staphylococci (CPS). Within the 105 CPS samples, 36 (9%) were identified as S. aureus, from which 8 (2%) were MRSA. Four (11.1%) of 36 S. aureus isolates, of which 3 (37.5%) were MRSA, had a multidrug resistance (MDR), and 6 MRSA strains were found positive for one or more SEs genes (seb, sed, and see). According to the ERIC-PCR analysis, only two S. aureus strains (one with personnel origin and one with carcass origin) were genetically identical. This study highlights the detection frequency of S. aureus in samples analyzed observed, while low, can be a significant public health problem, especially due to the identification of MRSA harboring some enterotoxin genes and having MDR.
Renoldi, NiccoloBrennan, Charles StephenLagazio, CorradoPeressini, Donatella...
11页
查看更多>>摘要：Psyllium seed husk (PSH) is a soluble dietary fibre with interesting health benefits, including reduction in blood glucose level in subjects with type 2 diabetes. Its supplementation in pasta represents a challenge due to a negative impact of high PSH levels on product acceptability. The aim of this work was to investigate the effects of the substitution of semolina with different levels of PSH on cooking properties, microstructure and in vitro glycaemic response of pasta. Dry pasta samples enriched with PSH were produced by replacing durum wheat semolina with 25, 50, 75 and 100 g/kg PSH. Cooked enriched pastas were firmer and sticker than the control. Cooking loss increased with increasing PSH levels above 25 g/kg with values below the technological acceptable limit of 80 g/kg. Semolina substitution with 50-100 g/kg psyllium was effective in lowering the predictive glycaemic response of enriched pasta in comparison with the control. Scanning electron microscopy and dough rheology (dynamic frequency and temperature sweep tests) suggested that this decrease was related to the formation of fibre aggregates limiting starch swelling. Semolina replacement with 50 g/kg PSH has the potential to provide a health benefit with minimal impact on cooking features of functional pasta.
NSTL
Elsevier