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LWT-Food Science & Technology
Elsevier
LWT-Food Science & Technology

Elsevier

0023-6438

LWT-Food Science & Technology/Journal LWT-Food Science & Technology
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    Fast detection of adulteration of aromatic peanut oils based on alpha-tocopherol and gamma-tocopherol contents and ratio

    Wang, HonglingZhang, YuquanShi, HaimingJiang, Yuanrong...
    5页
    查看更多>>摘要：A fast method based on normal-phase high-performance liquid chromatography with UV detection was applied to determine the tocopherols in aromatic peanut oil (APO) and four refined vegetable oils (soybean, sunflower, maize, and rapeseed oils). Our results showed that the tested oils varied greatly on the content of tocopherol isomers, especially on alpha- and gamma-tocopherol concentrations. Consequently, (alpha+gamma)-tocopherol (297.9-393.2 mg kg(-1)) and alpha-/gamma-tocopherol (1.05-2.13) were successfully applied as discriminating parameters for detecting the adulteration of APO with above four refined vegetable oils. Furthermore, APO was mixed with the four oils (at the levels of 5, 10, 15, 20 and 25 g/100 g, w/w) to determine whether the tocopherol analysis is a better approach than fatty acid profiling for detecting APO adulteration. Our results showed that for tocopherols, our detection limits were 5 g/100 g for soybean oil and 10 g/100 g for other three oils in APO, showing a higher sensitivity than fatty acids profile based method for detecting APO adulteration. Thus, our newly developed method is an alternative and innovative tool for fast and cost-effective detection of the adulteration of APO with soybean, sunflower, maize, and rapeseed oils.
      原文链接:
    • NSTL
    • Elsevier

    Protein enrichment of wheat bread with the marine green microalgae Tetraselmis chuii - Impact on dough rheology and bread quality

    Qazi, Waqas MuhammadBallance, SimonUhlen, Anne KjerstiKousoulaki, Katerina...
    9页
    查看更多>>摘要：Marine green microalgae are a sustainable source of high-quality protein. However, due to their green pigmentation and composition of volatiles, their incorporation into food products is a challenge. Incorporation of cell-wall disrupted Tetraselmis chuii (Tc) into bread (0, 4, 8, 12 and 16% wheat flour substitution) affected dough rheology and bread quality negatively. These effects were more pronounced at addition levels necessary for a EFSA nutrition claim on protein enrichment (12 and 16%). Treatment of Tc with ethanol not only removed much of the green pigmentation and volatiles, but also reduced the negative impact on dough rheology and bread quality. Doughs prepared with ethanol treated Tc (TcEt) showed a clear improvement in dough rheology evident as increased dough-stability-time (DST), resistance to extension (Rmax) and elastic-recovery-compliance (Je) particularly at substitution levels >4%. This was accompanied by an increase in bread quality e.g. at 12% substitution level specific volume increased from 2.1 to 2.69 mL/g, crumb firmness decreased from 1358 to 297 g and slice brightness increased from 25.2 to 49.0. Ethanol treatment of algae may be a feasible strategy to address the sensory and structural challenges that hinder incorporation of algae into foods at levels that can potentially confer nutritional benefits.
      原文链接:
    • NSTL
    • Elsevier

    A comparative study of aromatic characterization of Yingde Black Tea infusions in different steeping temperatures

    Liu, HaochengXu, YujuanWen, JingAn, Kejing...
    15页
    查看更多>>摘要：Black tea, known for its unique aroma, is one of the most popular non-alcoholic beverages. Because of complex aroma composition, studying black tea aroma has attracted widespread attention. The aim of this study was to evaluate the effect of different steeping temperatures (60 degrees C, 70 degrees C, 80 degrees C, and 95 degrees C) on the aroma composition of Yingde black tea for the first time. A total of 157 volatile compounds were identified by gas chromatographymass spectrometry (GC-MS). These compounds can be divided into 11 categories, including alcohols, esters, ketones, aldehydes, terpenes and sulfides. The types of different volatile compounds and contents in tea infusion samples show a positive correlation with steeping temperature. A total of 16 main aromatic compounds were identified though the comparison analysis of gas chromatography-olfactometry (GC-O FD = 32) data and odor activity value (OAV value = 1), including beta-damascone, beta-ionone, linalool, ethyl hexanoate, dimethyl sulfide, dimethyl trisulfide, nonanal, methyl salicylate, 3-hexenyl isovalerate, cedrol, and longifolene. A correlation of characteristic aroma data with descriptive sensory analysis (DSA) data clearly established that different steeping temperatures result in different overall aroma qualities of the black tea, indicating that steeping temperature is a key parameter affecting the aroma composition.
      原文链接:
    • NSTL
    • Elsevier

    The gel properties and gastric digestion kinetics of a novel lactic acid bacteria fermented tofu: Focusing on the effects of transglutaminase

    Yang, XiaoyuJiang, SiqiLi, Liang
    8页
    查看更多>>摘要：The purpose of this study was to evaluate the gel properties and gastric digestion of tofu made by combining transglutaminase (TGase) with lactic acid bacteria (LAB). TGase (0-7 U/g) significantly grew the tofu texture and water holding capacity, a significantly positive correlation between the hardness (R-2 = 0.78, P < 0.05), chewiness (R-2 = 0.72, P < 0.05), and WHC (R-2 = 0.71, P < 0.05) with TGase amount was found. When the TGase was 4 U/g, the tofu had the highest hardness ((45.89 +/- 0.88) g) and WHC ((76.56 +/- 2.40)%). A negative correlations between surface hydrophobicity and free sulphydryl content values of tofu with TGase amount were detected (R-2 = 0.90, 0.93, P < 0.01). With the extension of digestion time, the content of free amino acids (FAC) in tofu increased. It was found that the Logistic equation could be used to fit the relationship (an S-shaped curve) between FAC content (P) and the digestion time (t) of tofu. The equation was as follow: (P = KP0/P-0+(K-P-0)e(-rKt)) (R-2 = 0.964-0.998). Digestibility could be altered by controlling the amount of TGase and the structure of 2 U/g-tofu was in favor of the gastric digestion. The results of this study indicated that incorporation of TGase into tofu affects its digestibility and a theoretical foundation of tofu gastric digestion was established.
      原文链接:
    • NSTL
    • Elsevier

    Co-crystallized sucrose with propolis extract as a food ingredient: Powder characterization and antioxidant stability

    Irigoiti, YanetYamul, Diego K.Navarro, Alba S.
    9页
    查看更多>>摘要：Propolis possesses health beneficial properties due to its antioxidant compounds; however, its solubility in alcohol and its strong and unpleasant taste limit the use of propolis extract in foods. This study explores the encapsulation of a propolis ethanolic extract by co-crystallization in a sucrose matrix to eliminate the alcohol and to obtain a propolis powder with suitable technological properties and high antioxidant activity to be used as a food ingredient. The effect of the propolis extract on colour, moisture content, solubility, particle size distribution, flow properties and spectroscopic characteristics (FTIR) of the co-crystallized powders was determined. Polyphenols and flavonoids content and antioxidant capacity (ABTS and DPPH) during storage of the powders were also analysed. The propolis co-crystallized powders showed moisture contents below 2% and good flow properties, except at the higher content of the extract. The FTIR results showed that the presence of propolis did not alter the crystalline sucrose structure. Entrapment yields higher than 84% (flavonoids) and 78% (poly-phenols) were obtained. During storage of the powders high stability of these compounds was observed at light, darkness and refrigeration conditions. Thus, co-crystallization technique constitutes a low cost alternative for the protection of bioactive compounds of propolis.
      原文链接:
    • NSTL
    • Elsevier

    Tailored enzymatic treatment of Chlorella vulgaris cell wall leads to effective disruption while preserving oxidative stability

    Canelli, GretaMartinez, Patricia MurcianoHauser, Billie MaudeKuster, Isabelle...
    7页
    查看更多>>摘要：The green microalgae Chlorella vulgaris is a source of valuable nutrients, whose bioaccessibility is limited by the structurally complex cell wall. Enzymatic degradation of the cell wall represents a remarkable alternative to mechanical treatments due to its mildness and specificity. This work aimed to define an optimal combination of enzymes to increase the lipid and protein bioaccessibilities of C. vulgaris cells while preserving oxidative stability. Among the tested enzymes, chitinase, rhamnohydrolase, and galactanase caused the highest release of microalgae cellular material. Treatment with this enzymatic combination produced a slight increase in protein bioaccessibility, from 49.2% +/- 3.9% to 58.7% +/- 3.5%, but no increase in lipid bioaccessibility in comparison to the control. High-pressure homogenization (HPH) led to 61.8% +/- 2.6% lipid and 59.8% +/- 1.8% protein bioaccessibilities. Cell integrity was preserved after enzymatic treatment, while the mean particle size was reduced from 5 to 2 mu m after HPH. Oxidative stability was maintained over 3 months of accelerated shelf life in untreated and enzymatically treated C. vulgaris biomass while HPH caused drastic instability and off-flavour formation. Although more work is needed to optimise the enzymatic treatment to maximise the nutrient bioaccessibility, the presented process was successful in preserving lipid quality.
      原文链接:
    • NSTL
    • Elsevier

    Effect of electrostatic interactions and complexes formation between nisin and bacterial exopolysaccharides on nisin antimicrobial efficacy

    Abid, YousraBen Amara, ChediaGharsallah, HoudaDumas, Emilie...
    8页
    查看更多>>摘要：This study aims to describe interactions that may occur between nisin and bacterial exopolysaccharides (EPS) when they are present together in a model solution. For this purpose, two EPS, namely EPS-GM and EPS-BMS, produced by potential probiotic Bacillus tequilensis-GM and Leuconostoc citreum-BMS, respectively, were used. Results showed that maximal complexation occurred at pH 5.0 between anionic EPS (1.5 g/L) and cationic nisin (1 g/L) mainly through electrostatic interactions. Results provided by scanning electron microscopy, epifluorescence microscopy and turbidity measurements showed that EPS-GM was able to form bigger and higher amounts of complexes with nisin. The nisin antimicrobial activity was interestingly not affected and even improved after its complexation with EPS suggesting that these latter may act as protective agents of the nisin antimicrobial activity when applied in foods. The results of this study should help food technologists to optimize the physicochemical conditions for optimal formulation of food products containing EPS.
      原文链接:
    • NSTL
    • Elsevier

    Effects of blanching on drying characteristics, quality, and pectin nanostructures of dried cut-persimmons

    Oshima, TatsuyaKato, KodaiImaizumi, Teppei
    8页
    查看更多>>摘要：While blanching is mainly used for inactivating enzymes and pasteurization before processing of vegetables, this pretreatment is sometimes applied to improve the drying efficiencies of fruits and vegetables. However, the effects of blanching and drying on the composition and self-assembly properties of pectic substances in persimmons are unclear. In this study, fresh-cut persimmons were dried at 40, 50, 60, and 70 degrees C, with or without blanching. Blanching increased the rate of heated air-drying, the color intensity, and hardening. After blanching, water-soluble pectin (WSP) clearly decreased, and chelator-soluble pectin (CSP) increased. However, WSP increased with drying in all samples. Atomic force microscopy showed that the median height of WSP increased from 0.27 nm to 0.30 nm after blanching and decreased to 0.24 nm after drying. CSP and diluted alkali-soluble pectin (DASP) in fresh samples had a network structure. However, CSP in dried samples and DASP in blanched and dried samples lost these self-assembly properties. Our findings have implications for controlling the textures of dried fruits.
      原文链接:
    • NSTL
    • Elsevier

    Effects of tofu whey powder on the quality attributes, isoflavones composition and antioxidant activity of wheat flour pan bread

    Zhao, Chang-ChengLu, Ji-KeAmeer, Kashif
    9页
    查看更多>>摘要：Tofu whey, as the liquid by-product of tofu manufacturing, contain a high content of valuable nutrients. While, few studies have focused on the potential use of tofu whey as food ingredient. The study was aimed to evaluate effects of tofu whey powder (TWP) supplementation on physicochemical and functional properties of wheat flour pan bread. TWP-added breads showed significant decrease in baking loss but increase in specific volume, anti-oxidant activities, total phenolic and flavonoid contents of bread samples when increasing the addition levels of TWP. Isoflavone composition analysis showed genistein, daidzein, and glycitein as three major isoflavones, which indicated that the transformation of isoflavone glucosidic conjugates to aglycones was occurred during the bread making. While, at 4% or above addition levels, bread quality was negatively affected by TWP regarding both texture, color profiles and overall acceptance. As a by-product, TWP showed significant potential to improve the bread physicochemical and functional properties.
      原文链接:
    • NSTL
    • Elsevier

    Evaluation of melon drying using hyperspectral imaging technique in the near infrared region

    Netto, Jose Marcelino S.Honorato, Fernanda A.Kurozawa, Louise E.Barbin, Douglas F....
    8页
    查看更多>>摘要：The evaluation of the melon drying process under different pretreatments using hyperspectral images in near infrared (HSI-NIR) is presented as a quick and non-destructive means. Hyperspectral images of melon slices (3.0 cm x 3.0 cm x 0.3 cm) were obtained for different drying times. Principal Component Analysis applied to the images of cross sections of the dried samples without pre-treatment indicated that the water evaporation occurred unidirectionally. PLS models were generated for each drying pretreatment condition according to the moisture content based on their respective reference values. Prediction errors (RMSEP) obtained for these models were 3.79; 3.69; 3.24 and 2.98% moisture content under the following conditions, respectively: no pretreatment, ultrasound, vacuum, and the combination of vacuum and ultrasound. Chemical maps reveal that the use of vacuum and the combination of vacuum and ultrasound result in uniform drying, corroborating the results obtained by the drying kinetic curve, indicating that these pretreatments facilitate water diffusion in the samples.
      原文链接:
    • NSTL
    • Elsevier