•Germination greatly increased the proportions of bioaccessible antioxidants and starch.•Effects of HHP on the in vitro bioaccessibility of nutrients in GBR were evaluated.•HHP significantly increased the bioaccessibility of nutrients in GBR.•Effects of HHP processing on minerals bioaccessibility depended on the element species.•AFM revealed the changes induced by HHP processing on surface structure of GBR bran.The effects of germination and high hydrostatic pressure (HHP) processing on the in vitro bioaccessibility of mineral elements, amino acids (AAs), antioxidants and starch in brown rice (BR) were investigated. Germinated BR (GBR) was obtained by incubating at 37 °C for 36 h and then subjected to HHP treatments at 0.1, 100, 300 and 500 MPa for 10 min. The in vitro bioaccessibility of calcium and copper was increased by 12.59–52.17% and 2.87–23.06% after HHP, respectively, but bioaccessible iron was decreased. In addition, HHP significantly improved individual AAs, particularly indispensable AAs and gama-aminobutyric acid, as well as bioaccessible total antioxidant activities and starch resistance to enzymatic hydrolysis. However, germination greatly increased starch digestibility. Atomic force microscopy characterization suggested an obvious structural change in bran fraction at pressures above 300 MPa. These results can help to understand the effects of germination and HHP technologies on nutrients bioaccessibility and develop appropriate processing conditions.

•Lipid degradation of WBR processed by HHP, HIU and germination was evaluated.•Lipid hydrolysis and oxidation were enhanced by HHP and HIU, but inhibited by germination.•Lipase activities were improved by high pressure of 100 MPa, HIU and germination.•Different processing methods influenced mineral distribution in WBR.•PCA revealed a close relation between increased lipid oxidation and minerals.This work aimed at investigating the effects of emerging texture-improved processing techniques including high hydrostatic pressure (HHP; 150–450 MPa/10 min), high-intensity ultrasonication (HIU; 17.83 W·cm− 2/30 min) and germination (37 °C/36 h) pretreatments on lipid hydrolysis and oxidation development of wholegrain brown rice (WBR) during storage, in an attempt to ascertain a possible link between lipid degradation and the underlying mechanisms. The results showed that HHP and HIU treatments enhanced lipid hydrolysis and oxidation as indicated by the formation of free fatty acids (FFA) and thiobarbituric acid reactive substances (TBARS) respectively, whereas an opposite pattern was observed for germination. Storage process rather than after immediate treatments observed an increase in lipid oxidation of HHP and HIU-processed samples, which was related to processing-induced liberation of minerals. Quantitative and qualitative characterization via inductively coupled plasma-optical emission spectrometry (ICP-OES) and micro X-ray fluorescence (μ-XRF) analysis confirmed the shifts of mineral distribution in WBR grains in response to different pretreatments. The WBR-derived lipase was activated by Ca2 +, and μ-XRF mapping indicated calcium enrichment in pericarp/aleurone layer and its mobilization to embryo during germination process where magnesium and manganese were significantly reduced. Multivariate analysis revealed a close relationship between increased lipid degradation and minerals including magnesium and manganese. This is the first time for reporting the effects of selected texture-improved techniques on lipid stability of WBR grains across storage process as well as validating the involvement of processing-induced mineral release in lipid degradation.Download high-res image (513KB)Download full-size image

The use of a freeze-dried Tibetan kefir co-culture as a starter for production of Camembert-type cheese was investigated. Maturation of produced cheese was monitored for 35 days and the chemical composition, proteolysis, lipolysis, and volatile compounds were studied. The cheese underwent proteolysis. The content of pH 4.6-soluble nitrogen, 12% trichloroacetic acid-soluble nitrogen, and the total free amino acid content increased while the total nitrogen content decreased. Palmitic, myristic, oleic, and capric acid were the representative free fatty acids, which increased in amount during ripening. A total of 45 compounds were detected, including 16 acids, 8 ketones, 6 alcohols, 7 esters, and 8 unclassified compounds. Volatile carboxylic acids were abundant in the headspace of the cheese.

The aim of this research was to evaluate the effects of surfactants (span 80, tween 20 or the blend of above surfactants at the ratio of 1:1) on the properties of kudzu starch/ascorbic acid films. Each surfactant decreased surface tension of the film-forming solution and delayed the release of ascorbic acid from film to water. Tween 20 improved the wettability of film-forming solutions on both glass and paraffin wax substrates, and promoted the formation of V-type crystal in the films. The film's surface morphology was different depending on the surfactant types. The film containing only tween 20 showed higher flexibility, water content and solubility, lower mechanical strength, and comparable water vapor permeability when compared with the film containing only span 80. The film adding blended-surfactant was not only without better morphology, wettability and mechanical properties but had the worst water barrier ability as regarding the film containing single surfactant.

Kudzu starch–chitosan composite films were prepared by combining 2% (w/v) gelatinized kudzu starch and 2% (w/v) chitosan solution together. Effects of acids (acetic acid, lactic acid and malic acid) to dissolve chitosan on properties of the composite films were investigated. Fourier-transform infrared spectra showed that kudzu starch and chitosan could form miscible films. X-ray diffraction data indicated that the crystalline of each single component was suppressed after film forming process. The composite film using malic acid as solvent showed the best antimicrobial activity against Escherichia coli and Staphylococcus aureus, which may be due to the highest amount of dissolved amino group, the lowest water sorption ability and the best water barrier property. The film chose acetic acid as solvent presented the strongest mechanical property, the smallest solubility, the lightest yellowness and color. The film made from lactic acid solution displayed the greatest flexible property demonstrated by the maximum elongation.

To investigate the effects of low O2 and high CO2 atmospheres on the berry drop of ‘Kyoho’ grapes (Vitis vinifera X V. labrusca), changes of fruit detachment force (FDF) and berry abscission and enzyme activities in the abscission zone were examined during 60 days of storage in air (control), 4%O2 + 9%CO2 or 4%O2 + 30%CO2 at 0 °C and 95%relative humidity. There was a high negative correlation between FDF and berry drop. Cellulase activity increased over time and was closely correlated with berry abscission. Polygalacturonase (PG) activity rose markedly for the first 30 days and then remained relatively constant. Peroxidase (POD) activity dropped significantly for the first 15 days and subsequently rose sharply (P < 0.05). Cellulase, PG and POD activities were the lowest in fruits in 4%O2 + 30%CO2, followed by 4%O2 + 9%CO2 and air storage. Pectinesterase (PE) maintained a basal level of activity and there were no significant differences among three treatments (P < 0.05). Compared to air control, the combined effects of the lower level of O2 and the higher level of CO2 suppressed the activities of cellulase, PG and POD, maintained greater FDF, and reduced berry abscission during storage.

Yellow peaches (Prunus persicu L. Batsch.) were stored under controlled atmospheres (CA) of 2% O2 + 5% CO2, 5% O2 + 10% CO2, 2% O2 + 10% CO2, 5% O2 + 5% CO2, and normal atmosphere at 2 °C, to investigate the effects of different concentrations of O2 and CO2 on the structure of a single sodium carbonate-soluble pectin (SSP) molecule. The microstructure changes, including aggregates and branches, were studied by atomic force microscopy (AFM) at initially, on the 15th and 45th day. The microstructure of SSP molecules and polymers showed that aggregates separated gradually with the storage time. The degradation took place in the linear backbone as well as in side chains. The degradation of SSP molecules was inhibited by lower O2 and higher CO2 concentrations. Almost all of the chains were composed of four basic units with widths of 11.719, 15.625, 19.531 and 17.578 nm, which can be visualized and calculated exactly by AFM. This indicated that parallel linkage or intertwist between the basic units was a fundamental characteristic of SSP molecules.

•The effects of HPP and SAEW on the structure of B. cereus spores were evaluated.•HPP-SAEW treatment could cause spore’s damage, even an incomplete exosporium.•Spores treated with HPP-SAEW had an irregular surface bumps detected by TEM.•Approximately 90% of DPA was released in the groups of treated by HPP-SAEW.•Inactivation mechanism possibly relies on proteins susceptible to SAEW under HPP.The aim of this study was to investigate the effects of high pressure processing (HPP) and slightly acidic electrolysed water (SAEW) on the structure of B. cereus spores in order to understand the inactivation mechanism. The physiological response of spores was studied by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), dipicolinic acid (DPA) release, su­per-res­o­lu­tion mul­ti­pho­ton con­fo­cal mi­cro­scope (SMCM), and flow cytometry (FCM). The morphology of B. cereus spores treated with HPP-SAEW exhibited a large fraction damage, and also an incomplete exosporium. Furthermore, spores treated with HPP-SAEW had an irregular surface bumps, and even a critical distortion. Approximately 90% of DPA was released in the groups of treated by HPP-SAEW, and 80% of DPA was released in single HPP treatment groups. The SMCM and FCM results indicated that HPP-SAEW methods was not mainly depended on germination, but directly killed. The mechanism of HPP-SAEW possibly was that one of the proteins was particularly susceptible to SAEW under HPP conditions.

•The Tg and water state in carrot tissues were explored using DSC and NMR.•With increasing time, FID caused changes in the water state in dehydrated carrots.•FID caused a shift from free water to immobilized water in carrot tissues.•FID could elevate Tg values mainly by reducing immobilized water in carrot tissues.The effect of far-infrared drying (FID) on the water state and glass transition temperature (Tg) of carrots were assessed by nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC). Results showed that, with increasing time, FID caused dramatic changes in the water state in dehydrated carrots. The drastically decreased content of free water in vacuoles was accompanied by sharp increases in the content of immobilized water in the cytoplasm and extracellular space. Subsequently, the content of immobilized water decreased gradually with increasing time. FID elevated the Tg values appreciably by decreasing the content of immobilized water in carrot tissues. In carrots with moisture content <0.39 g/g dry matter, Tg values were increased by 21.36, 35.55 and 40.99 °C with the moisture content decreased by 0.20, 0.25 and 0.30 g/g dry matter at respective infrared power values of 400, 600 and 800 W.

The effect of transport vibration on the quality of Huanghua pears (Pyrus pyrifolia Nakai, cv. Huanghua) during commercialization (room temperature) after transport was tested. Different vibration levels on the front and rear floors in a 2-tonne truck with leaf-spring suspensions were evaluated for their effect on mechanical damage to fruit during transport. Changes in color and cell membrane permeability of pear skin, flesh firmness, hydrolase activities and cell wall constituents were examined in fruit stored for up to 36 days after transport. Our data suggest that the damage levels of pears loaded on different positions in the truck were significantly different (p < 0.05) and pears in top containers of columns were damaged more heavily than this in bottom containers (p < 0.05). Physical and chemical results showed that mechanical damage caused by different vibration levels to pears affected plasma membrane integrity of skin cells and contents of the polysaccharide components in the cell walls of pear tissue, which contributed to color change and softening of pears during subsequent commercialization after transport.

We studied the quality and internal changes in Huanghua pears (Pyrus pyrifolia Nakai, cv. Huanghua) coated with shellac, Semperfresh™ (sucrose polyester base coating), and carboxymethyl chitosan (CMC) during cold storage (4 °C). The changes in respiration rate, weight loss, cell membrane permeability and texture profile analysis (TPA) such as hardness, brittleness and chewiness were recorded periodically for up to 60 days after harvest to compare the effects of the applied coatings. Magnetic resonance (MR) imaging was used to inspect the internal characteristics of pears after storage. The soluble solids contents (SSCs), titratable acidity (TA), ascorbic acid concentration, and taste scores were also measured. Our data suggest that shellac coating was more effective in reducing the respiration rate and weight loss and in maintaining the quality of pears than Semperfresh and CMC coatings.

•A strategy using HHP to maintain rice flavor of GBR was proposed.•Germination decreased most of aromas in BR, but HHP greatly enhanced that of GBR.•Aldehydes, alcohols and ketones were major volatiles in GBR increased by HHP.•Chemometrics clearly separated BR, GBR and HHP-treated GBR grains by aroma profiling.•PLS-DA confirmed 4-vinylguaiacol as a bio-marker for BR germination.Germination favors to significantly enhance functional components and health attributes of whole-grain brown rice (BR), but the production of germinated BR (GBR) compromises the typical rice flavor perception due to soaking process. Simultaneously, high hydrostatic pressure (HHP) is considered as an effective processing technique to enhance micronutrients utilization efficiency of GBR and improve products flavor, but no information about the effects of HHP treatments on volatile fingerprinting of GBR has been reported. Therefore, the objective of this work was to apply HHP to improve the flavor and odor of GBR grains by exploring HHP-induced changes in aroma compounds. GBR grains were obtained by incubating at 37 °C for 36 h, and subsequently subjected to HHP treatments at pressures 100, 300 and 500 MPa for 15 min, using 0.1 MPa as control. Headspace solid-phase micro extraction coupled to gas chromatography mass spectrometry was used to characterize process-induced shifts of volatile organic compounds fingerprinting, followed by multivariate analysis. Our results confirmed the significant reduction of total volatile fractions derived from germination process. Contrarily, the following HHP treatments greatly enhanced the flavor components of GBR, particularly characteristic odorants including aldehydes, ketones, and alcohols. Principal component analysis further indicated the different influence of germination and high pressure on the changes in volatile components. Partial least square-discrimination analysis suggested that 4-vinylguaiacol was closely linked to germination, whereas E,E-2,4-decadienal, E-2-hexenal, E,E-2,4-heptadienal and benzyl alcohol could be considered as volatile biomarkers of high pressure.Download high-res image (267KB)Download full-size image

•A strategy using HHP to maintain rice flavor of GBR was proposed.•Germination decreased most of aromas in BR, but HHP greatly enhanced that of GBR.•Aldehydes, alcohols and ketones were major volatiles in GBR increased by HHP.•Chemometrics clearly separated BR, GBR and HHP-treated GBR grains by aroma profiling.•PLS-DA confirmed 4-vinylguaiacol as a bio-marker for BR germination.Germination favors to significantly enhance functional components and health attributes of whole-grain brown rice (BR), but the production of germinated BR (GBR) compromises the typical rice flavor perception due to soaking process. Simultaneously, high hydrostatic pressure (HHP) is considered as an effective processing technique to enhance micronutrients utilization efficiency of GBR and improve products flavor, but no information about the effects of HHP treatments on volatile fingerprinting of GBR has been reported. Therefore, the objective of this work was to apply HHP to improve the flavor and odor of GBR grains by exploring HHP-induced changes in aroma compounds. GBR grains were obtained by incubating at 37 °C for 36 h, and subsequently subjected to HHP treatments at pressures 100, 300 and 500 MPa for 15 min, using 0.1 MPa as control. Headspace solid-phase micro extraction coupled to gas chromatography mass spectrometry was used to characterize process-induced shifts of volatile organic compounds fingerprinting, followed by multivariate analysis. Our results confirmed the significant reduction of total volatile fractions derived from germination process. Contrarily, the following HHP treatments greatly enhanced the flavor components of GBR, particularly characteristic odorants including aldehydes, ketones, and alcohols. Principal component analysis further indicated the different influence of germination and high pressure on the changes in volatile components. Partial least square-discrimination analysis suggested that 4-vinylguaiacol was closely linked to germination, whereas E,E-2,4-decadienal, E-2-hexenal, E,E-2,4-heptadienal and benzyl alcohol could be considered as volatile biomarkers of high pressure.Download high-res image (267KB)Download full-size image

•FFA and moisture of GBR increased after UHP treatment.•The peak values of bioaccessible minerals were at 300 MPa whereas it decreased at 500 MPa.•Starch gelatinization of GBR occurred at 300 MPa and was further enhanced at 500 MPa by SEM.•All TPA parameters other than springiness of GBR were highly correlated (p < 0.01) after UHP.•Minerals bioaccessibility had a positive relationship with hardness, chewiness and springiness by CCA.Ultra-high pressure (UHP) is considered as an effective processing method to enhance micronutrients utilization efficiency in germinated brown rice (GBR), but there is little information available for the effects of UHP treatments on mineral bioaccessibility and related structural characteristics. Therefore, this work examined the changes induced by UHP in the in vitro bioaccessibility of selected minerals and structural and textural properties at pressures, as well as their potential relationship. UHP treatments were applied at 100, 300 and 500 MPa for 10 min, and 0.1 MPa as control. Proximate analysis showed that free fatty acids (FFA) and moisture in GBR greatly increased after UHP treatment. Three representative minerals with different levels were chosen to assess the bioaccessibility, including phosphorus (P), magnesium (Mg) and manganese (Mn). The results demonstrated that the minerals bioaccessibility, measured by percentage solubility, were the highest when at 300 MPa whereas it decreased at 500 MPa. Correspondingly, microstructure imaging by scanning electron microscope (SEM) showed that the gelatinization of starch granule occurred at 300 MPa and it became more obvious when increased to 500 MPa. Starch gelatinization significantly lowered the hardness of GBR grains, simultaneously accompanied with the decrease of cohesiveness, gumminess and resilience through texture profile analysis (TPA). Multivariate analysis by principal component analysis and canonical correspondence analysis indicated a highly intra-associated (p < 0.01) TPA parameters and a close correlation between the bioaccessibility and hardness, chewiness and springiness. These results provide information on minerals bioaccessibility and structural properties of uncooked GBR after UHP treatment, which could lay the foundation for further elucidating the correlation between structure and micronutrients bioaccessibility.Download high-res image (236KB)Download full-size image

The effects of high O2 on catabolic enzymes and anatomical structure in abscission zones, fruit detachment force (FDF), and berry drop of grapes were investigated. ‘Kyoho’ table grapes (Vitis vinifera x V. labrusca) were subjected to air or 80% O2 at 0 °C in 95% relative humidity for 60 days. During storage, separation occurred at the berry-pedicel indentation and the abscission layer extended gradually from lateral phloem towards the whole phloem and pith, forming intercellular cavities and leading to berry drop. FDF declined steadily accompanied by an increase in berry drop. Grape abscission was correlated to the increases in activity of hydrolases, in particular cellulase (Cx) and polygalacturonase (PG), in abscission zones. In contrast to air storage, high O2 inhibited Cx, PG and pectinesterase (PE) activity and the reverse for peroxidase (POD), decreased the degree of swelling and distorting of the abscission cell walls, and tended to keep berry adherence strength high and reduced berry drop. The inhibitory mechanism of high O2 on berry drop possibly could be explained by the fact that disassembly of the abscission zone cells was delayed by a synergistic impact on degradation enzymes whose activities were affected by high O2 levels.