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Quality changes to bog bilberry juice at different pH levels (pH 2.67 and 3.60) during a 14‐day Lactobacillus plantarum (L. plantarum B7 and L. plantarum C8‐1) inoculation process was investigated in terms of changes in reducing sugars, amino acids, biogenic amines, total anthocyanins, total phenolic content, and juice color. Results showed that bacterial strains grew better in the pH adjusted juice (pH 3.60), and L. plantarum B7 was less able to utilize reducing sugar than L. plantarum C8‐1 in both pH conditions during the entire inoculation process. Most amino acids and biogenic amines decreased at this level, while the γ‐aminobutyric acid increased in the juice after inoculation. Malic acid and amino acids were consumed faster in the juice to yield a high level of lactic acid. The total anthocyanin content in the juice was reduced, whereas no significant alteration was observed in the total phenolic content after inoculation. The juice showed an increase in the L* value but a decrease on the a* value, with the b* value approaching 0. The adjusted pH juice displayed a higher L* value but lower a* and b* values after inoculation. Multivariate analyses indicated that the pH value and the inoculation time played key roles in altering the quality of the juice after inoculation, while the strain effect was mainly observed in the pH adjusted juice. Our results provide useful information on how to improve the quality of low pH berry juice by inoculating L. plantarum. Novelty impact statement: The results indicate that the quality of juice could be improved by controlling the inoculation conditions and time of Lactobacillusplantarum. The paper provides useful information on how to improve the quality of low pH berry juice by inoculating L. plantarum. [ABSTRACT FROM AUTHOR]

The combination effect of microwave (MW) irradiation, ε‐poly‐L‐lysine (ε‐pL), and calcium propionate (CP) on the shelf life and quality of Qingke barley fresh noodles (QBFN) stored at 4 ± 1°C were investigated in terms of total plate count (TPC), bacterial diversity, water characteristics, and noodle qualities. The results showed that the initial TPC of the control and MW + ε‐pL + CP groups were 4.40 log cfu/g and 3.75 log cfu/g, respectively. The combination of MW, ε‐pL and CP effectively inhibited the growth of microorganisms, and the shelf life of the MW + ε‐pL + CP group extended from 6 days (control) to 12 days. Compared with the control, the MW + ε‐pL + CP group maintained the better noodle quality, color, cooking quality, and relatively higher abundance of strong bound and weakly bound water during the storage. Practical applications: This study may provide a basis data for further study about the changes of bioactive compounds, antioxidant activities, digestible properties, and volatile compounds in Qingke barley fresh noodles QBFN stored at law temperature, as well as offer data for manufacturers to promote its industrialization. [ABSTRACT FROM AUTHOR]

Changes of microbes, bioactive compounds, protein structures, and noodle qualities in Qingke barley (one of the Tibetan barleys) fresh noodles (QBFN) stored at 25°C were evaluated. The results showed that an increase in total plate count (TPC) and total mold count (TMC) occurred after 12 hr, and Pantoea, Erwinia, Bacillus for the bacteria, Penicillium and Aspergillus for the mold became dominant spoilage microorganisms at the end of storage.In addition, according to the microbial growth at 25°C, the microbial growth models were built for both TPC and TMC, and the microbial growth models were well fitted by logistic model, with higher fitting precision. The fitting equations were Y = 3.7642–3.7/[1+(t/26.597)3.1], R2 = 0.9942 and Y = 1.7553–1.7546/[1+(t/19.8)3.4], R2 = 0.9999. Due to the polyphenol oxidization (PPO), the total phenol and flavonoid contents decreased from 77 and 36 mg/100 g to 49 and 18 mg/100 g, respectively. The pH value, color, textural properties, and cooking quality decreased significantly (p < .05). The disulfide (SS) bond content decreased from 2.9 to 1.6 µmol/g, while the free sulfydryl (SH) content increased from 0.9 to 1.3 µmol/g; the cost of a significant reduction in α‐helix induced an increase in the random coil with the deterioration of QBFN. The relative abundance of strong bounded water decreased while the relative abundance of weakly bounded water and free water increased, which indicated the destruction of the structure of protein encapsulating starch in QBFN. Moreover, Pearson correlation analysis showed that changes of TPC, TMC, SS/SH bond content, and water state were also significantly correlated with the appearance, textural properties, and cooking quality of QBFN. Practical applications: Investigating changes in microbe diversity, bioactive compound, protein structure, water state, and noodle quality during storage at 25 ± 1°C will help us understand the mechanisms and dynamics of QBFN deterioration. Identification of the dominant microbes that contribute to noodle spoilage and the changes of bioactive compounds help us determine suitable methods to inhibit the growth of microbes and to prevent the loss of bioactive compounds. Moreover, correlation analysis may help us understand the relationship between noodle quality and microbe, water state, and protein structure, and provide a theoretical basis for improving noodle quality. [ABSTRACT FROM AUTHOR]

ε‐poly‐L‐lysine (ε‐PL) is a cationic polypeptide. As a natural antibacterial peptide, it has attracted much attention in the food, biomedical, and chemical industries because of its wide antibacterial spectrum and safety. Use of ε‐PL in the food industry is common, due to its biological activity and functional properties. This paper focuses on the physiochemical properties, safety, antibacterial activity, antibacterial mechanism of action, and applications of ε‐PL in improving the quality and shelf life of various foods. Practical applications: As green consumerism is becoming more popular, there is a growing demand for natural preservatives. This work provides basic theories and methods for the application of ε‐PL in food preservation. This paper gives scientific guidelines for consumers and producers of agricultural products. Thus, it may promote the utilization of ε‐PL in the food industry and reduce the use of chemical preservatives. [ABSTRACT FROM AUTHOR]