pH-indicative Films Based on Chitosan–PVA/Sepiolite and Anthocyanin from Red Cabbage: Application in Milk Packaging

Biobased smart packaging is been the most interesting research field.In this study,pH-sensitive films based on anthocyanin molecules from red cabbage and sepiolite mineral nano-clay as functional additives were studied.The films were fabricated by casting method of blend polymer Chitosan/Poly(Vinyl Alcohol)at two fillers loading(5wt.%and 10wt.%).The structural,morphological,thermal,optical,hygroscopic,and mechanical properties as well as the pH sensitivity of films were investigated.The thermal properties confirm that the amount of the anthocyanin in sepiolite was around 6.4%.The tensile strength and the young’s modulus of produced composites at 10wt.%sepiolite–anthocyanin content was increased to 8.90 MPa and 163 MPa,respectively.The maximum water absorption that the films may absorb was 12.3%.pH sensitivity analysis showed that the Smart films change the color by changing the pH level,from pink at pH lower than 6 to yellow at pH higher than 6.Thus,the developed pH-sensitive films show band gaps in visible light that make them useful for monitoring milk spoilage.

Red cabbage washing with acidic electrolysed water:effects on microbial quality and physicochemical properties

The effects of acidic electrolysed water(AEW)as‘green’technology on the microbiological and physicochemical properties of fresh-cut red cabbages were studied.Fresh-cut red cabbages and artificially inoculated red cabbages with Salmonella typhimurium DT104 were washed with distilled water(DW)and different available chlorine concentrations(ACC)of AEW for different times.AEW treatments significantly reduced the populations of native aerobic bacteria,molds,and yeasts,and artificially inoculated S.typhimurium DT104 compared with the DW-treated and untreated red cabbage samples.The effectiveness of AEW treatments was greatly enhanced with increasing ACC and treatment times.S.typhimurium DT104 were not detected in the washing water that were collected after the red cabbages treated by AEW.The surface colour,pH,and total phenolic contents did not significantly change when the red cabbages were washed with DW and AEW containing 100 mg/L available chlorine for 3 min.The anthocyanin contents and antioxidant activities of red cabbage were significantly reduced by 18.5 per cent for cyanidin,22.1 per cent for pelargonidin,and 11.2 per cent for 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical scavenging activity,however,the impacts on the nutritional benefits of red cabbage were considered as limited and acceptable.The optimal process condition of AEW for washing red cabbage was 100 mg/L ACC for 3 min.In these conditions,most of the native microflora were inactivated,and artificially inoculated S.typhimurium DT104 on the red cabbage were reduced by 40.2 per cent[3.67 log CFU/g(log10 colony-forming units per gram)]and with minimal losses of nutrients and antioxidant activity,as well as no requirement of decontamination treatment on the washing water after AEW treatment.

Morphology and glucosinolate profiles of chimeric Brassica and the responses of Bemisia tabaci in host selection,oviposition and development

Plant structures and chemicals, which are developed from the shoot apical meristem（SAM）, form the main barriers to insect feeding. A plant chimera containing cells of different genetic origins in the SAM will be morphologically and chemically different compared with the parents and thus may result in differential resistance to herbivores. In this study, we explore if particular elements of plant resistance are localized in one of the layers of SAM; the replacement of one cell layer in a chimera may be linked to change of a single resistance trait to herbivores. The morphology and glucosinolate profiles of two periclinal chimeras（labeled as TTC and TCC, respectively） and grafted parents tuber mustard（labeled as TTT） and red cabbage（labeled as CCC） were compared and the performance of whitefly（Bemisia tabaci） in host selection, oviposition preference and development were assessed under controlled conditions. Both chimeras possessed leaf trichomes as parent tuber mustard TTT, however, TTC had significantly more trichomes than TCC and parent TTT. Leaf wax content of both chimeras was intermediate between the two parents. Five aliphatic and two indole glucosinolates were detected in both chimeras, whereas three aliphatic glucosinolates（3-methyl-sulfinylpropyl, 4-methyl-sulfinylbutyl and 2-hydroxy-3-butenyl） were not detected in tuber mustard, and one aliphatic glucosinolate（3-butenyl） was not detected in red cabbage. Unexpectedly for a chimera, the quantities of two aliphatic glucosinolates（3-methyl-sulfinylpropyl and 4-methyl-sulfinylbutyl） in both TTC and TCC were 3-to 5-fold higher than parents. In olfactory preference assays, B. tabaci showed preference to CCC, followed by TCC, TTC and TTT, and number of eggs laid showed the same pattern： CCC〉TCC〉TTC〉TTT. Interestingly, more whiteflies landed on TTT plants than the other three types in a free choice experiment and the developmental duration from egg to adult was the shortest on TTT and increased in the order TTT