Evaluation of Lactococcus lactis subsp. lactis as protective culture for active packaging of non-fermented foods: Creamy mushroom soup and sliced cooked ham

Recent advances and role of melatonin in post-harvest quality preservation of shiitake (Lentinula edodes)

Shiitake mushrooms are renowned for their popularity and robust nutritional value, are susceptible to spoilage due to their inherent biodegradability. Nevertheless, because of their lack of protection, these mushrooms have a short shelf life. Throughout the post-harvest phase, mushrooms experience a persistent decline in quality. This is evidenced by changes such as discoloration, reduced moisture content, texture changes, an increase in microbial count, and the depletion of nutrients and flavor. Ensuring postharvest quality preservation and prolonging mushroom shelf life necessitates the utilization of post-harvest preservation techniques, including physical, chemical, and thermal processes. This review provides a comprehensive overview of the deterioration processes affecting mushroom quality, covering elements such as moisture loss, discoloration, texture alterations, increased microbial count, and the depletion of nutrients and flavor. It also explores the key factors influencing these processes, such as temperature, relative humidity, water activity, and respiration rate. Furthermore, the review delves into recent progress in preserving mushrooms through techniques such as drying, cooling, packaging, irradiation, washing, and coating.

Effects of Saccharomyces cerevisiae and Kluyveromyces marxianus on the Physicochemical, Microbial, and Flavor Changes of Sauce Meat during Storage

Saccharomyces cerevisiae (S. cerevisiae) and Kluyveromyces marxianus (K. marxianus) are often used as fermenters in yogurt and alcohol, and have been less studied within meat products. The yeasts were added to sauce meat, and the uninoculated group served as a control in this study to examine and compare the changing patterns of physicochemical and flavor characteristics of S. cerevisiae and K. marxianus on sauce meat during storage. The changes in moisture content, aw, pH, thiobarbituric acid reactive substances (TBARS), and other flavor characteristics were measured in sauce meat during the first, second, fourth, and sixth months after production. The following factors were examined: moisture content, aw, pH, TBARS, peroxide value (POV), acid value (AV), soluble protein (SP), free amino acid (FAA), and volatile flavoring compounds. With VIP > 1 and p < 0.05 as the screening conditions, the partial least squares model (PLS-DA) was used to assess the distinctive flavor components in the sausages. The findings demonstrated that the three groups' changes in sauce meat were comparable during the first two months of storage but differed significantly between the 4th and 6th months. The moisture content, water activity, and pH of the sauce meat decreased gradually with the storage time; TBARS, AV, and FAA increased significantly; SP decreased significantly from 2.61 to 1.72, while POV increased to 0.03 and then decreased to 0.02. The POV and TBARS values of the yeast-infected meat were substantially lower than those of the control group, and the POV and TBARS values of the meat inoculated with S. cerevisiae were particularly decreased (p < 0.05). The POV and TBARS values of SC (S. cerevisiae group) decreased by 49.09% and 40.15%, respectively, compared to CK (the control group) at the time of storage until June. The experimental group (KM: K. marxianus group) significantly increased the SP and FAA values of the sauce meat (p < 0.05) by 32.4% and 29.84% compared to the CK group, respectively. Esters and olefins as well as alcohols and esters were much greater in meat that had been supplemented with S. cerevisiae and K. marxianus than in meat from the control group. In conclusion, inoculating sauce meat with S. cerevisiae can significantly enhance the quality and flavor of sauce meat while it is being stored.

Novel gellan gum-based probiotic film with enhanced biological activity and probiotic viability: Application for fresh-cut apples and potatoes

A novel probiotic film based on gellan gum (GN), cranberry extract (CE), and Lactococcus lactis (LA) was developed in the present study. The fluorescence and SEM image results showed that GN/CE film containing LA was successfully fabricated. The incorporation of LA significantly enhanced the antibacterial activity of the film. The presence of CE strengthened the antioxidant activity and LA survivability in the film. The combination of LA (0-1.0 %) and CE (0.5-1.0 %) improved the mechanical property of the film through the formation of density structure. The best comprehensive properties were obtained with the film containing 2.0 %LA and 0.5 %CE. The GN/2.0 %LA/0.5 %CE film also showed the optimal preservation effect on fresh-cut potatoes and apples. Hence, GN/2.0 %LA/0.5 %CE probiotic film has proved to be suitable for fruit and vegetable preservation.

Advances in the Role and Mechanisms of Essential Oils and Plant Extracts as Natural Preservatives to Extend the Postharvest Shelf Life of Edible Mushrooms

China has a large variety of edible mushrooms and ranks first in the world in terms of production and variety. Nevertheless, due to their high moisture content and rapid respiration rate, they experience constant quality deterioration, browning of color, loss of moisture, changes in texture, increases in microbial populations, and loss of nutrition and flavor during postharvest storage. Therefore, this paper reviews the effects of essential oils and plant extracts on the preservation of edible mushrooms and summarizes their mechanisms of action to better understand their effects during the storage of mushrooms. The quality degradation process of edible mushrooms is complex and influenced by internal and external factors. Essential oils and plant extracts are considered environmentally friendly preservation methods for better postharvest quality. This review aims to provide a reference for the development of new green and safe preservation and provides research directions for the postharvest processing and product development of edible mushrooms.

Comparison of non-volatile flavor compounds in Stropharia rugosoannulata soup processed by different methods

In this study, we investigated the non-volatile flavor compounds (5'-nucleotides, free amino acids, organic acids and soluble sugars) in Stropharia rugosoannulata soup under different processing treatments. S. rugosoannulata soups were first obtained from S. rugosoannulata powder of three different particle sizes under both thermal and non-thermal treatments. Then, the effects of processing methods on non-volatile compounds in these S. rugosoannulata soups were investigated. Specifically, the non-thermal treatment of high hydrostatic pressure (HHP) resulted in high levels of equivalent umami concentration (EUC, 827.44-1411.79 mg/100 g DM); ultrasonic treatment (UT) and homogenization (HG) led to high concentrations of soluble sugars (15.58-30.48 mg/g DM); while hot treatment (HT) contributed to high contents of total organic acids (65.52-98.39 mg/g DM). Besides, moderate fine grinding of S. rugosoannulata powder (P2) facilitated the release FAAs (free amino acids) and soluble sugars in the soup. These results suggested that HHP-P2 is beneficial to the preservation of non-volatile compounds in S. rugosoannulata soup. Our findings may improve the utilization of S. rugosoannulata in the soup industry.

Impact of lactic acid bacteria on the control of Listeria monocytogenes in ready-to-eat foods

Due to the increased demand for ready-to-eat (RTE) minimally processed foods, alternatives to chemical and thermal preservation methods to maintain food safety are highly demanded. A significant safety hazard in RTE food products is the growth of the foodborne pathogen Listeria monocytogenes. After processing, recontamination or cross-contamination of L. monocytogenes in RTE food products may occur and the lack of cooking can lead to an increased risk of listeriosis. Further, some RTE food products (e.g., cheese and cured meat) can have a long processing period and shelf life, thus allowing for the growth and proliferation of L. monocytogenes in the food matrix. Lactic acid bacteria (LAB) are generally recognized as safe (GRAS) probiotics and have been proposed as a biological control approach to eliminate foodborne pathogens including L. monocytogenes. LAB have been reported to extend the shelf life of food products and inhibit pathogen proliferation via growth competition and metabolite production. LAB are native microflora of many RTE foods, but only certain LAB may inhibit pathogen growth. Therefore, specificity of LAB species should be employed into their use in RTE foods. This review will discuss the antimicrobial mechanisms of LAB against L. monocytogenes, selective use of LAB in food matrices, and their uses in food processing and packaging.