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Starches from sixteen cassava germplasms harvested at the same time in the Hainan region were evaluated for their physicochemical and structural properties. The granule morphology of all the isolated cassava starch samples showed round, bell or oval shapes and exhibited the same A-type crystalline pattern. The crystallinity range was 26.6–30.8%. The selected cassava germplasms showed a wide variation in granule size distribution: The D[4,3] (the average particle size) ranged from 13.49 μm to 306.27 μm. The water absorption capacity (192.6–226.7%), oil absorption capacity (185.0–216.9%) and transparency (6.8–16.5%) indices varied significantly among the cassava germplasms. However, the retrogradation rates of the cassava starch pastes increased rapidly during the first 1 h and then stabilized. The solubility of starch increased with the temperature. In addition, the FTIR (Fourier Transform Infrared Spectrometer) ratios of 1045/1022 cm−1 and 1022/995 cm−1 of the sixteen cassava starches varied in the range of 1.06–1.78 and 0.78–1.04, respectively. These results indicated that the granule size, relative crystallinity, degree of short-range order, water and oil absorption capacities, solubility and transparency of the cassava starches were greatly influenced by the variety of cassava, which could help in determining the advantages of these starches for applications in different food and nonfood industries.

Different pretreatments can affect the quality of Hypsizygus marmoreus (HM). In this study, the effects of thermal treatment or combined with color protection and hardening on color, texture, microstructure, polyphenol oxidase (PPO) and Peroxidase (POD) C-1: Explain the first time? activities, and the volatile components of HM were investigated. The results showed compared with the control group, both heating group (H group) and color protection, hardening and heating (CHH group) significantly enhanced the color difference, and reduced all texture parameters as well as PPO and POD activities. Additionally, in two treatment groups, the structure of HM became loose, the amounts of alcohols, ketones, and aldehydes were changed significantly. Compared with the H group, the color difference and PPO activities in CHH group were significantly decreased, while all texture parameters were increased significantly, the fibers of HM showed regular arrangement. In conclusion, the combination of CHH performed better effects on hardness, chewiness, microstructure, and enzymes activities related to enzymatic browning.

Dielectric properties of sliced Agaricus bisporus samples, with 0.16–0.89 [g/g, wet basis (w.b.)] moisture content, were determined using a network analyser and an open-ended coaxial-line probe, over a frequency range of 915 MHz to 2450 MHz and a temperature range of 25°C to 60°C. The results showed that the permittivity of A. bisporus was a function of frequency, moisture content, and temperature. The dielectric constant and loss factor were directly proportional to moisture content and temperature, respectively, and both decreased with increasing frequency. However, the influence of temperature on the dielectric constant showed a different trend, as this was affected by the moisture content of the sample. The dielectric loss factor initially increased and then decreased with the decrease in moisture content. Both inflection points appeared at the moisture content value of 0.69 (g/g, w.b.), which represents the “semi-bound water transfer” point. Third-degree polynomial models could be used to describe dielectric constant and loss factor values as functions of moisture content and temperature. The penetration depth decreased with increasing frequency and temperature; however, this first decreased with decreasing moisture content and then increased. Notably, the penetration depth was at a low ebb when the moisture content ranged from 0.69 to 0.52 (g/g, w.b.), indicating easier uneven drying. Low frequency (915 MHz) with large penetration depth represents a highly effective method for large-scale industrial dielectric microwave drying of A. bisporus slices from the angle of uniformity.

The current study was aimed to investigate the effect of glucosinolate degradation on the flavor precursors and pungent odors in raw and microwaved rapeseeds. Five isothiocyanates and six sulfur compounds were identified using comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GC× GC-TOF/MS). Comprehensive analysis with headspace solid-phase microextraction (HS-SPME) and aroma extract dilution analysis (AEDA) with altering split ratio showed that 1-isothiocyanato butane, allyl isothiocyanate and 4-isothiocyanato-1-butene were responsible for the sulfur, pungent and green odors in rapeseed oils, due to their high flavor dilution factor. Dimethyl sulfide, dimethyl trisulfide and dimethyl sulfoxide, might be derived from methionine or isothiocyanate rearrangement reactions imparted onion-like, cabbage-like, garlic-like, and sulfurous-pungent odors. Rapeseed samples were heated in a microwave for seven minutes, and the total glucosinolate content decreased from 28.2 ± 0.8 μmol/g to 14.5 ± 0.6 μmol/g in Brassica napus, from 101.2±3.0 μmol/g to 42.2 ± 5.4 μmol/g in Brassica campestris, and from 132.02 ± 9.31 μmol/g to 52.50 ± 6.50 μmol/g in Brassica juncea, compared to untreated ones. Differences in the concentrations of six main odorants and the glucosinolate precursors from genetic types were responsible for the intensity of the pungent odors in raw and microwaved rapeseeds. The result can assist to determine the flavor of the commercial rapeseed oils.

A novel aged garlic extract, with high antioxidant activities, was prepared by soaking sliced garlic in 10% ethanol solution for 90 days. In order to locate the antioxidant ingredients of aged garlic extract, 2,2-azinobis-6-s (3-ethylbenzothiazoline sulfonic acid) assay, hydroxyl free radical assay, 2,2-diphenyl-1-picrylhydrazyl assay, and ferric reducing/antioxidant power assay were conducted to guide the fractionation of aged garlic extract by means of extraction. As a result, the ethyl acetate fraction was identified as the highest antioxidant activity in aged garlic extract. Therefore, the ingredient information of the ethyl acetate fraction were obtained through gas chromatography–mass spectrometry and ultra performance liquid chromatography mass spectrometry / mass spectrometry analysis. Some phenols and diallyl disulphide, 5-(hydroxymethyl)-2-furancarboxaldehyde, S-allyl-cysteine, S-allyl-mercaptocysteine, and 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid were identified as potent antio...

By analyzing 14 food allergen-specific IgG antibodies in 1299 children residing in Henan province of China, we aimed to gain a preliminary understanding of food intolerance in children living in this region. Specific IgG antibodies for 14 food allergens were semi-quantitatively detected in the sera of subjects using enzyme-linked immunosorbent assays. The total positive rate for food allergen IgG antibodies was 99.9%. Of the 14 food allergens tested, sera most frequently tested positive for specific IgG antibodies for the following five food allergens, listed from the highest positive rate to the lowest: egg, milk, soybean, cod, and crab. The total positive rate for each food allergen-specific IgG antibody showed no statistically significant gender-based differences (p > 0.05), nor did the total positive rate for IgG antibodies for all the types of food allergens (p > 0.05). The positive rates of allergen-specific IgG antibodies for milk, beef, chicken, pork, mushrooms, and eggs (p < 0.05) showed a statis...

An improved thermal conductivity probe system consisting of a probe heater, control circuits and data test system was developed and described. It has the merits of the short duration of the experiments, simplicity, high accuracy, and relatively small sample requirement. The measurement time is about 20 s. The effective volume of sample is 50 ml. Calibration of the probe with glycerin and ethanol in this work exhibits an accuracy of 1.4% and 1.9%, respectively. The probe system was used to measure the thermal conductivity of orange juice. The measured thermal conductivity values were linearly dependent on the concentration and temperature of the orange juice. A decrease in the concentration of orange juice and an increase in the temperature resulted in an increase in the values of thermal conductivity. However, the influence of concentration on the thermal conductivity of orange juice was stronger than that of temperature. An empirical model for the thermal conductivity of orange juice as a function of con...

The rheological behavior of cabbage pulp was determined using a computer controlled rotational rheometer at a temperature range of 20, 30, 40, and 50°C. The flow behavior of pulp was pseudoplastic and fitted well to the Casson model. In all the cases, the effect of soluble solids on apparent viscosity was more pronounced than the effect of temperature. The combined effect of temperature and soluble solid content on viscosity was also given. The activation energy value of 3–6°Brix cabbage puree varied from 7 to 12.6 kJ/mol when shear rate increased from 1 to 10 s−1. The exponential model developed had an excellent fit (r2 > 0.87) and would be useful for the engineering applications.

The microstructure of bayberry juice hazes after storage at 25°C for 6 months was examined by light microscopy and transmission electron microscopy. Haze particles were found spherical and elliptical surrounded by translucent membranes. The transmission electron microscopic study indicated that the particles had three substructures: stain impenetrable central “core,” stain penetrable middle part, and floccule–like outer space structure. The “core” and the middle part of the haze were assumed to be the polyphenols or polyphenol/protein complexes, and the outer space was mainly the protein component. These particles were found to be aggregated to form dentrite or leaf–like structures supposedly due to hydrophobic and covalent links.

Eight different combinations of pretreatments and storage methods (freezing rate, maltose treatment and storage temperature) were applied to frozen kiwifruit slices, and the effect of these treatments on the qualities (color, water content, chlorophyll content, ascorbic acid content and cell structure) were evaluated. Color, water content, chlorophyll and ascorbic acid contents of frozen kiwifruit stored below the glass transition temperature (Tg′) were higher than those of kiwifruit slices stored above the glass transition temperature, and the cell structure of the former were more integrated than that of the later. The effects of freezing rate and sugar treatment on the qualities of frozen kiwifruit slices showed diversity according to the experimental factors and index.