Luu, PhillipChhetri, Vijay SinghJanes, Marlene E.King, Joan M....
6页
查看更多>>摘要：Gaseous chlorine dioxide, a strong oxidizing agent can be utilized as an effective alternative sanitizing agent. This study evaluated the efficacy of low concentration (<= 5 mg/L) gaseous chlorine dioxide (ClO2) treatment with gas permeable sachets in reducing the levels of Salmonella, E. coli O157:H7, and Listeria monocytogenes on strawberries and blueberries. Strawberries and blueberries were spot inoculated (10(7) CFU/g) with multi-strain cocktails of each pathogen and dried for 120 min inside a biosafety cabinet. A treatment chamber was successfully designed to sanitize inoculated samples in sealed 5 gallon chambers containing gaseous ClO2 sachets. The gaseous ClO2 overhead concentration was maintained within the range of 3.32 +/- 1.73 to 4.95 +/- 2.19 mg/L for up to 3 h of treatment. Gaseous ClO2 treatments reduced pathogen levels significantly (P < 0.05) on strawberry and blueberry samples. The reduction of E. coli O157:H7, L. monocytogenes, and S. enterica levels on strawberries were by 2.0 +/- 0.83, 3.5 +/- 0.18, and 2.9 +/- 0.20 log CFU/g, respectively after 3 h of treatment while 3 hof gaseous ClO2 treatment on blueberries reduced E. coli O157:H7, L. monocytogenes, and S. enterica levels by 2.3, 2.1 +/- 0.28, and 2.2 +/- 0.63 log CFU/g, respectively. The reduction of pathogen levels with treatment time was variable based on pathogen type. This study indicates that gaseous ClO2 delivered in gas permeable sachets at low concentrations (<= 5 mg/L) can significantly reduce pathogens on strawberries and blueberries during postharvest sanitation.
查看更多>>摘要：The drying and utilization of potato pulp have become a bottleneck problem of the potato starch industry. In this study, the process of pectinase and cellulase-assisted fermentation was assessed regarding their effects on the microbial composition and drying of potato pulp. Enzyme-assisted fermentation increased the levels of organic acids, specifically lactic acid, acetic acid, and citric acid. Enzyme-assisted fermentation promoted the growth of Lactobacillus plantarum, which inhibited the growth of bacterial and fungi. Scanning electron microscopy and light microscopy showed that pectinase-assisted fermentation degraded cell walls, altering the microstructure and colloidal properties of potato pulp. Reduction in the water holding capacity and viscosity by pectinase-assisted fermentation improved the drying properties. Texture profile analysis also revealed higher hardness and lower cohesiveness values of potato pulp. Quick drying analysis indicated that pectinase-assisted fermentation could facilitate rapid drying of potato pulp. Based on these findings we could develop more efficient methods for drying and utilization of potato pulp.
查看更多>>摘要：To developed stable double emulsions (DEs) that were resistant to environmental stress, native corn starch (NCS) or high-amylose starch was used as material to prepare starch-based double emulsions (SDEs). The effects of temperature (4-60 degrees C, pH 7.0, 0 mmol/L NaCl), pH (2.0-8.0, 25 degrees C, 0 mmol/L NaCl), and NaCl concentration (10-100 mmol/L, 25 degrees C, pH 7.0) on the droplet size distribution, particle size, microstructure, interfacial rheology, and interfacial tension of the SDEs were evaluated. Results revealed that DEs stabilized by NCS of 7 g/100 mL concentration (7% NCS DEs) had the small mean particle size (4.80 +/- 0.56 mu m) with type-A structure, a high elasticity (14.98 Pa) and toughness (132.85 Pa) interfacial film. Moreover, the relationship between the different SDEs structures and their physical stability confirmed that 7%NCS DE exhibited excellent physical stability and was resistant to heat, acid and alkali conditions, and salt, owing to their dense network structure (Tan delta<1) and stable interfacial tension (39.85 +/- 0.03 mN/m). This study demonstrates the potential of SDEs provides new practical applications.
查看更多>>摘要：The relationship between diet and gut microbial community is widely studied, and foods that might be sources of beneficial microorganisms have garnered interest. Here, we analyzed the changes in the microbial community of kyejang, a traditional Korean fermented beverage, made with nuruk, cinnamon, and medicinal herbs fermented at 10, 20, and 30 degrees C for 7 days. Using selective media, the decrease in the numbers of Bacillus pumilus, B. amyloliquefaciens, and B. subtilis colony-forming units was observed from the initial fermentation stage to day 7, whereas those of Leuconostoc mesenteroides and Lactobacillus curvatus increased during this period. Next-generation sequencing revealed 719 operational taxonomic units (OTUs) at the onset of fermentation of kyejang (control), confirming the presence of diverse microorganisms. Leuconostoc spp. was dominant for 7 days at 10 degrees C and 20 degrees C, whereas Lactobacillus spp. was dominant for 7 days at 30 degrees C. Therefore, the microbial community of fermented kyejang was dominated by lactic acid bacteria; however, the number of OTUs decreased to 43 within 7 days of fermentation at 30 degrees C, indicating that the microbial community simplified as fermentation proceeded. Based on these results, kyejang is expected to contribute to the diversity of gut lactic acid bacteria and traditional beverages.
查看更多>>摘要：The aim of this work is to investigate how volatile compounds of Chinese steamed bread (CSB) are influenced by yeast level (0.5, 1 and 1.5%, flour weight basis), fermentation time (20, 40 and 60 min) and steaming time (5, 10, 20 and 30 min). The volatile compounds were extracted by headspace-solid phase microextraction and analyzed by gas chromatography-mass spectrometry. Higher yeast level and longer fermentation time promoted the formation of yeast-metabolism-derived compounds, including 2-methyl-1-propanol, 3-methyl-1-butanol, phenethyl acetate, hexyl acetate and 2-octanone. Increased fermentation time decelerated the generation of lipid oxidation compounds (octanal, nonanal, decanal, (E)-2-nonenal, and (E,E)-2,4-decadienal). Prolonged steaming time facilitated the production of benzaldehyde and 2-pentylfuran and promoted the loss of alcohols and esters. Network analysis showed that 2-pentylfuran contributed to wheat-like aroma of CSB while 3-methyl-1-butanol was related with alcoholic odor. This study was helpful for improving the understanding of CSB aroma evolution profile and may contribute to the aroma improvement of commercial CSB.
查看更多>>摘要：The objective of this study was to evaluate the effects of extremely low oxygen partial pressure storage (ELO) maintained in static or dynamic controlled atmosphere monitored by chlorophyll fluorescence (DCA-CF) in the aerobic and anaerobic metabolism and its effects on physiological disorders and quality of 'Royal Gala' apples after 9 months, plus 7 days at 20 degrees C. Several static CA conditions were evaluated and compared to DCA-CF. Fruit stored under 0.4 kPa O-2 + 1.0 kPa CO2 had similar quality maintenance as fruit stored under DCA-CF. Fruit stored under these two conditions were also healthier and had higher flesh firmness and lower flesh breakdown than CA-stored fruit. The partial pressure of oxygen (pO(2)) decreased to 0.15 kPa O-2 + 0.0 kPa CO2 resulted in high anaerobic metabolism (acetaldehyde, ethanol, and ethyl acetate accumulation), which damaged fruit cells and led to low oxygen injury and consequently fewer healthy fruit amount.
查看更多>>摘要：The effects of L-histidine (His) and L-lysine (Lys) on the emulsifying and interfacial properties of porcine myofibrillar proteins (MPs) at low/high ionic strength were investigated to improve physical stability of MPs emulsion at low ionic strength. Results showed that His and Lys increased emulsion stability index, and decreased creaming index at low ionic strength, but caused no significant changes in both indexes at high ionic strength. Additionaly, His and Lys increased the emulsifying activity and apparent viscosity, but decreased the droplet size at both ionic strength. His and Lys also promoted the diffusion of MPs and increased the interfacial pressure. Meanwhile, the interfacial loading of MPs was increased (p < 0.05) by 16.07% and 12.79% at low ionic strength, and by 8.85% and 8.24% at high ionic strength in the presence of Lys and His, respectively. Raman spectra revealed that the alpha-helix content of MPs was decreased (p < 0.05) by 5.05% and 11.79% at low ionic strength, and by 12.14% and 7.23% at high ionic strength in the presence of Lys and His, respectively. In summary, His and Lys enhanced the stability of MPs emulsion at low ionic strength via changing the structure and interfacial behaviour of MPs.
查看更多>>摘要：The purpose of this research was to develop protein-based composite fruit and vegetable printing inks with good printability. The printing characteristics and sensory evaluation properties of five different animal and vegetable proteins as a matrix and fruit and vegetable powder composite printing ink were studied. Results showed that the ink based on peanut protein isolate exhibited the best printing characteristics. The extruded line diameter is 0.83 mm closest to the nozzle diameter, and the height change is only 0.3 mm within 120 min, which is significantly better than other protein inks and has high self-supporting and precision. Moreover, the peanut protein-based ink also scored 7.78 points in the sensory evaluation experiment, which was significantly higher than other protein inks. This showed that the ink based on peanut protein can be well accepted by consumers, which also makes the research more feasible and practical. In this research, the universality of peanut protein-based ink was tested. The results showed that for different fruit and vegetable powders, the composite fruit and vegetable ink based on peanut isolate protein has stable and better printing properties. This provides certain prerequisites for the development of different peanut protein isolate-based inks, and provides the possibility to solve the diversity of different nutrition customization problems and improves consumer acceptability.
查看更多>>摘要：The quality characteristics and consumer acceptability of strawberries depend on their ripening stages. Pelargodinin-3-glucoside (P3G) is the main anthocyanin in strawberries and changes during postharvest distribution. Hyperspectral imaging technology (HSI), which covers the ranges of visible-near infrared (VIS-NIR) and shortwave infrared (SWIR) light, was used to predict the P3G of strawberries for two types of harvest maturity, half maturity (HM) and full maturity (FM) during distribution periods. Spectral data was extracted from hyperspectral images of strawberries at the two stages of maturity and partial least square (PLS) regression was used to develop the prediction model of P3G. The highest prediction accuracy was 86% in HM using the SWIR region. Meaningful wavelengths to develop the PLS model were approximately 970, 1,153, 1,303, and 1,445 nm for moisture, carbohydrates, and anthocyanin. Moreover, the spatial information of P3G accumulation can be also analyzed using HSI. The overall results indicated that HSI could be used for the prediction of P3G with different harvest maturity of strawberry. Additionally, this technology could provide the information of distribution periods of strawberry by monitoring changes of pigment of strawberries.
查看更多>>摘要：Baijiu is a highly-valued traditional Chinese distilled alcoholic liquor and maturation markedly improves its sensory qualities and market value. Identification of age-markers is challenging because of the complexity of the endogenous chemical profile and the absence of exogenous components added during maturation. Here, freshly-distilled raw Lu-flavor Baijiu samples were stored for two years and non-targeted screening for age-markers based on the volatile profile characterized by solid-phase micro-extraction assisted GC-MS. The resulting volatile datasets were analyzed by partial least-squares discriminant analysis, Spearman's correlation and Random-forest decision-tree, to identify potential age-markers. The contents of long chain fatty acid ethyl esters varied the most during maturation, mostly being absent in freshly-distilled Baijiu, but appearing at different times. Similar behavior was observed in bottled samples matured up to four years. In addition, a slight increase in short/medium chain fatty acid ester content was observed. Unsupervised PCA analysis, applied only to the fatty acid ethyl ester dataset, was able to distinguish between bottled Baijiu samples matured for one, two, three, or four years. These age-markers may help establish a reliable model for verifying the maturation time of Lu-flavor Baijiu. This screening approach should be adaptable to other alcoholic liquors, for quality assessment and authenticity testing.
NSTL
Elsevier