Colour and chlorophyll level modelling in vacuum-precooled green beans during storage

Influence of different pre-cooling methods on the freshness preservation of bok choi(Brassica rapa var. chinensis)

Several pre-cooling methods for bok choi were used, such as natural convection pre-cooling (NCPC), strong wind pre-cooling (SWPC), vacuum pre-cooling (VPC), cold water pre-cooling (CWPC), electrolyzed water pre-cooling (EWPC), and fluid ice pre-cooling (FIPC), in order to determine the most suitable precooling method. It was found that VPC reduced the respiration rate, inhibited the increase of malondialdehyde (MDA) and relative electrolyte leakage, and significantly decreased the total bacterial count. This may be due to the rapid decompression process during vacuum pre-cooling, which disrupts the microbial structure and has a certain sterilizing effect. Bok choi pre-cooled by VPC had the best color, hardness value, chlorophyll, titratable acid (TA) content, vitamin C (VC) content, total phenolic (TP) content, soluble sugar content, superoxide dismutase (SOD) activity, ascorbate peroxidase (APX) activity, and catalase (CAT) activity. Therefore, the most suitable pre-cooling method for bok choi among the above pre-cooling methods was the VPC method.

Ultrasound synergistic slightly acidic electrolyzed water treatment of grapes: Impacts on microbial loads, wettability, and postharvest storage quality

Microbial contamination is the principal factor in the deterioration of postharvest storage quality in grapes. To mitigate this issue, we explored a synergistic treatment which combines ultrasound (US) and slightly acidic electrolyzed water (SAEW), and rigorously compared with conventional water cleaning (CW), exclusive US treatment, and standalone SAEW treatment. The US + SAEW treatment proved to be markedly superior in reducing total bacterial, mold & yeast counts on grapes. Specifically, it achieved reductions of 2.23 log CFU/g and 2.76 log CFU/g, respectively, exceeding the efficiencies of SAEW (0.78, 0.75), US (0.58, 0.65), and CW (0.24, 0.46). The efficacy of this synergistic treatment is attributed to the ultrasound removal of the wax layer on grape skins, which transitions the skin from hydrophobic to hydrophilic. This alteration increases the contact area between the grape surface and SAEW, thereby enhancing the antimicrobial efficacy of SAEW. From a physicochemical quality standpoint, the US + SAEW treatment exhibited multiple advantages. It not only minimized weight loss, color deviations, polyphenol oxidase activity and malondialdehyde synthesis in comparison to CW-treated samples but also preserved firmness, sugar-acid ratio and the activities of key enzymes including phenylalanine ammonia-lyase, superoxide dismutase and catalase, and thus maintaining high levels of total phenolics, total ascorbic acid, total anthocyanins, and antioxidants. Consequently, US + SAEW treatment put off the times of decay onset in grapes by 12 days, outperforming both SAEW (8) and US (4) in comparison to CW. These results highlight the potential of US + SAEW as an effective strategy for maintaining grape quality during their postharvest storage period.

Effects of Different Pre-Cooling Methods on the Shelf Life and Quality of Sweet Corn (Zea mays L.)

The strong wind pre-cooling (SWPC), ice water pre-cooling (IWPC), vacuum pre-cooling (VPC), natural convection pre-cooling (NCPC), and slurry ice pre-cooling (SIPC) techniques were used to pre-cool the fresh sweet corn (Zea mays L.), and then the pre-cooling treated sweet corn samples were stored at 4 °C for 28 days. During refrigeration, quality indicators, such as hardness, water loss, color, soluble solids content, and soluble sugar, were determined. In addition, oxidation indicators, such as peroxidase, catalase, ascorbic acid-peroxidase activity, and carotene content, were also measured. The results showed that the main problems of sweet corn during cold storage were water loss and respiration. The pre-cooling speed of SWPC is the fastest, and the latent heat of sweet corn can be removed in only 31 min. SWPC and IWPC could reduce the loss of fruit quality, maintain good color and hardness, inhibit the decrease of water, soluble solids, soluble sugars, and carotenoid contents, maintain balance between POD, APX, and CAT, and extend the shelf life of sweet corn. The shelf life of SWPC and IWPC corn reached 28 days, 14 days longer than SIPC and VPC treated samples, and 7 days longer than NCPC treated samples. Therefore, SWPC and IWPC are the appropriate methods to pre-cool the sweet corn before cold storage.

3D Food Printing: Principles of Obtaining Digitally-Designed Nourishment

Three-dimensional printing (3DP) technology gained significance in the fields of medicine, engineering, the food industry, and molecular gastronomy. 3D food printing (3DFP) has the main objective of tailored food manufacturing, both in terms of sensory properties and nutritional content. Additionally, global challenges like food-waste reduction could be addressed through this technology by improving process parameters and by sustainable use of ingredients, including the incorporation of recovered nutrients from agro-industrial by-products in printed nourishment. The aim of the present review is to highlight the implementation of 3DFP in personalized nutrition, considering the technology applied, the texture and structure of the final product, and the integrated constituents like binding/coloring agents and fortifying ingredients, in order to reach general acceptance of the consumer. Personalized 3DFP refers to special dietary necessities and can be promising to prevent different non-communicable diseases through improved functional food products, containing bioactive compounds like proteins, antioxidants, phytonutrients, and/or probiotics.