Journal of Food Processing and Preservation最新文献

This study evaluated the change in the carotenoid content and colorimetric properties of the pumpkin flower (Cucurbita maxima) in convective drying. Three factors were studied: drying temperature (45, 50, and 55°C), airflow (0.3, 0.6, and 0.9 m/s), and shape of the flower (whole, half, and petals). The initial lightness value of 64.38 tends to decrease with drying temperature and time; however, the lightness increases as the pumpkin flower shape passes from the petals to the whole shape because of the high moisture content. During drying, the a and b parameters ranged from 16.61 to 30.03 and 34.61 to 61.46, respectively. An increment in a value indicates that the pumpkin flower tends to be redder, and the increase in b values indicates a yellow color movement. The hue angle increased when the airflow goes from 0.3 to 0.9 m/s and when the drying temperature increased from 50 to 55°C; therefore, the pumpkin flower tended to be more yellow when the drying temperature passed from 50 to 55°C. The best properties of pumpkin flowers were obtained during the drying process at a temperature ranging from 50 to 55°C. At this temperature range, moisture content was around 3.11% to 10.2% and water activity was from 0.225 to 0.334, respectively. It was also noted that drying at higher temperatures leads to loss of color and carotenoid content because of the presence of heat-sensitive molecules, which is also why low drying temperature is used in this process.

The aim of this study was to detect the electrochemical characteristics of rice leaves under low-temperature stress. This study uses the electrical impedance graph method and the electrolyte exostosis method under the condition of low-temperature cold case study in the seedling stage of rice leaves, with a normal seedling stage of rice crops grown as controls. The shape of the electrical impedance map of rice leaves under low-temperature stress and its change with the increase of low-temperature stress were studied, and the change trend of electrical impedance map parameters with the increase of low-temperature stress was statistically analyzed. At the same time, the two detection methods are discussed to establish the correlation. The results showed that the electrical impedance pattern was a complete, symmetrical, single half arc with rice leaves subjected to reversible damage. The left side of the arc starts to disappear with an irreversible injury. Rice tended to die when the arc on the right side of the impedance spectrum began to scatter. Moreover, the change in the electrical impedance spectrum was consistent with that of relative conductivity. When the rice was not dead, the extracellular resistance and relaxation time of leaves decreased with the increase of stress degree, and intracellular resistance increased. Indicating the electrical impedance spectroscopy (EIS) can be employed as a nondestructive testing method to detect physiological characteristics of rice leaves under low-temperature stress.

Jiang-flavor Daqu is the starter used in the production of Jiangxiangxing Baijiu, as it is the primary source of microorganisms. The production of Jiangxiangxing Baijiu heavily relies on the use of Jiang-flavor Daqu, wherein the quality of the latter is intricately associated with the surrounding environment during the Daqu-making process. The objective of this study was to investigate the evolution pattern of microbial communities in the Daqu-making environment as the Daqu room application period increased and determine their role in shaping Jiang-flavor Daqu microbial communities. There was a certain level of overlap observed in the dominant microbial genera between the Daqu-making environment of Jiang-flavor Daqu and Jiang-flavor Daqu itself. Consequently, this may explain the close relationship observed in both bacterial life activities. And there was also a strong correlation between the ground and air fungal communities in the Daqu-making house during various usage periods. Furthermore, the composition of microbial communities in the air, the composition of microbial communities in the ground, the bacterial function in the air, and the bacterial function in the ground displayed varying degrees of similarity. However, it is worth noting that the microbial community structure undergoes changes with the gradual increase in the usage time of the fermentation chamber, leading to differences in microbial markers between various fermentation chambers. Most importantly, the quantity of bacteria, molds, and yeasts in the production environment during the initial use stage of the Daqu room was generally advantageous. Additionally, the microbial community in Jiang-flavor Daqu primarily originates from the initial production environment in the Daqu room. The study demonstrated that the microbial community structure in the Daqu room during the early stage significantly contributes to the formation of the microbial community structure in Jiang-flavor Daqu. These findings provide novel insights for improving the quality of Jiang-flavor Daqu.

Currently, a limited understanding of how packaging and storage conditions affect product quality is a major factor contributing to the short shelf life of seasoning powder products. To address this problem, the objective of this study was to explore the impact of four types of packaging and different temperature conditions (ranging from 5 to 45°C) during 110 days of storage on product quality, specifically the moisture content, astaxanthin content, and total aerobic microbial count. The packaging materials investigated included aluminum film-coated polyethylene bags (Al/PE bag), kraft paper-coated polyethylene bags (PE/kraft paper bag), polyethylene terephthalate (PET bottle), and glass bottles. Kinetic models of degradation astaxanthin, moisture absorption, and aerobic microbial growth were developed. The results indicated that PET bottles were the most effective packaging material to maintain the moisture content and astaxanthin levels. Furthermore, temperatures between 5 and 15°C were found to be optimal for the preservation of astaxanthin content, the stabilization of moisture content, and the inhibition of microbial growth. At the same time, first-order, Peleg, and Gompertz models are suitable for describing the mechanism of transformation for astaxanthin, moisture, and microbial aerobic growth with a value of R² > 0.9. These findings provide valuable information for selecting the appropriate packaging and storage conditions that can extend the shelf life of seasoning powder products.

Oxidation reactions negatively impact the taste and shelf life of the oils. Antioxidants are commonly employed to mitigate the development of off-flavors and rancidity and thereby extend the shelf life of oil. In response to consumers’ increasing demand for healthy foods, there is a notable focus on incorporating naturally sourced antioxidants. Yarrow plant is a good source of natural antioxidants which could be used in improving the quality of the oils. Therefore, in this study, adaptive ANFIS was employed to investigate the extraction of antioxidant compounds from the yarrow plant using the pulsed electric field-ultrasound method. The extraction process was performed at varying pulsed electric field intensities (0.25, 3.25, and 6.25 kV/cm) and different ultrasound durations (20, 40, and 60 minutes). Then, the impact of incorporating the plant extract on the oxidation parameters of sesame oil was assessed during storage. Results demonstrated that the extraction efficiency consistently increased with rising pulsed electric field intensity and ultrasound treatment time. However, the levels of total phenol, DPPH, and ascorbic acid content initially increased and then decreased at higher pulsed electric field intensity during longer ultrasound treatment. Furthermore, an increase in acidity and thiobarbituric acid index was found during prolonged storage time, while the peroxide level in the samples peaked on the 5th day of storage before declining. The high correlation coefficients between experimental results and model outputs underscored the models’ accuracy, representing their efficacy in controlling the extraction conditions using the pulsed electric field intensity-ultrasound extraction method and utilizing the extract in sesame oil.

The following reports on the efficacy of a gas-phase hydroxyl radical-based process for decontaminating shredded lettuce on a laboratory and simulated commercial scale. The process is based on the ultraviolet light at 254 nm UV-C-mediated degradation of hydrogen peroxide mist and ozone gas to generate antimicrobial hydroxyl radicals. Escherichia coli K12 was applied as a surrogate for E. coli O157:H7, and at laboratory scale, the hydroxyl-radical process (1.5% vol/vol H₂O₂ delivered at 40 ml/min, UV-C dose 114 mJ/cm², 20 ppm ozone, 29°C chamber temperature, and 30 s residence time) could support a 1.63 ± 0.61 log CFU reduction. This is compared to the 0.57 ± 0.18 log CFU reduction obtained for a chlorine-based wash. In scale-up, batches (2-10 kg) of E. coli inoculated romaine lettuce were passed through sequential hydroxyl-radical reactors. Here, the units were elevated to create a cascade effect, with the hydrogen peroxide mist being introduced as an intermister between the reactors. It was found that the three units placed in sequence with intermisters supported a 2.05 ± 0.10 log CFU reduction of E. coli, thereby verifying that homogenous treatment had been achieved. Additional trials operated the hydroxyl-radical process at 4°C without loss of performance. The hydroxyl-radical process was not negatively affected by applying a pretreatment wash. The study has demonstrated that the hydroxyl-radical process can be applied as an alternative to postharvest wash to enhance the food safety of romaine lettuce.

The search for a new antibiotic or antifungal that could function efficiently without side effects or inadequacies was always a dilemma. For centuries, mushrooms have been praised for their medicinal powers. Recent studies show that many mushroom species possess antimicrobial compounds that inhibit or kill bacteria, fungi, and other microbes. These studies attributed the antimicrobial potency of mushrooms to the presence of active compounds called phytochemicals. Mushrooms have been found to contain an abundance of phytochemicals such as phenolics, terpenoids, flavonoids, alkaloids, steroids, saponins, and polysaccharides. These compounds can inhibit cell wall synthesis and disrupt membrane permeability or redox balance. This review highlights the current knowledge about the phytochemical content of mushrooms, their antimicrobial properties, and some extraction strategies. The antimicrobial effects of various microorganisms, such as foodborne pathogens, drug-resistant bacteria, and fungi, are discussed. Critical limitations in using mushrooms as antimicrobial sources include safety risks from toxins, variability in compound potency between species, extraction and purification challenges, inconsistent yields, scalability issues, and regulatory hurdles for commercial applications. Overall, this article shows that mushrooms are prosperous of various antimicrobial compounds that can benefit human health.

The wet market poultry processing is a concern of spreading microbial pathogens into the environment or to the products. So, this study evaluated the microbiological contamination in poultry settings, i.e., slaughter and processing lines of wet market poultry shops, and the use of nonchlorine sanitizer to improve the sanitation. Swab samples from inner drum surfaces, defeathering machine inner surfaces, knife surfaces and workers’ hands, drum’s water, feather/carcass, and debris were collected, and their microbiological quality was determined. Most of the samples including workers’ hand surfaces were heavily contaminated with coliform, fecal coliform (Klebsiella pneumoniae, Enterobacter spp.), E. coli, Salmonella enterica, and yeast and mold. The antibiotic sensitivity/resistivity test showed that E. coli was resistant to 9 antibiotics, K. pneumoniae to 8 antibiotics, S. enterica to 5 antibiotics, and Enterobacter spp. to 4 antibiotics, which were found common to all the bacterial isolates against 11 antibiotics. Additionally, in comparison to hot water washing, nonchlorine sanitizer (0.01% calcinated calcium from scallop or eggshell source) was found to effectively reduce pathogens from the surfaces of wet market poultry slaughter and processing lines. Hence, the use of nonchlorine sanitizer could be a novel practice to improve the hygiene and safety status of wet market poultry slaughterhouses and processing environment as well as reduce occupational hazard associated with poultry processing.