Effects of ultrasonic treatment on the surface bacteria of Lyophyllum decastes during storage.

This study explores the relationship between the storage quality and bacterial microflora in the mushroom Lyophyllum decastes. The surface bacteria of L. decastes were separated by combining the traditional culture plate separation and 16S rRNA sequencing method, to study the effects of ultrasonic (US) treatment on the surface bacteria of L. decastes during storage. The results demonstrated that Pantoea agglomerans and Pseudomonas fluorescens were among the 15 culturable bacteria isolated with traditional plate method during storage, belonging to 2 phyla and 7 genera. US treatment could inhibit the growth and significantly increase cell membrane permeability, and contents extravasation in P. agglomerans, though its inhibitory effect on P. fluorescens was less. The 16S rRNA sequencing revealed, bacteria from 9 phyla and 35 genera were isolated, and P. fluorescens was the dominant species throughout the storage time. These results indicated that the composition of mushroom surface microflora of Control (CK) and US groups are similar, and the bacterial microflora networks analysis also showed a positive correlation. The KEGG annotation for the functional classification of the bacteria showed that a total of 328 pathways were acquired at the KEGG l3 level, and the relative abundance of membrane transport, amino acid metabolism, carbohydrate metabolism, and energy metabolism pathway was high. Moreover, the relative abundance of the surface bacteria of L. decastes also decreased. Hence, the US treatment had a better bacteriostatic effect, maintained the whiteness index and firmness, and improved the sensory quality of L. decastes during storage.

Goat milk powder supplemented with branched-chain fatty acid: influence on quality and microstructure.

BACKGROUND: Branched-chain fatty acid (BCFA) is effective in preventing and helping to treat neonatal necrotizing enterocolitis. It is essential to supplement goat-milk powder for formula-fed preterm infants with BCFA. In this study, the quality and microstructures of milk powders supplemented with different concentrations of BCFA were evaluated, using goat milk powder without BCFA as the control group (CG). RESULTS: In comparison with the CG, goat milk powder supplemented with BCFA exhibited smaller fat globules and a significant drop in overall particle size. During 16 weeks of storage, BCFA-supplemented groups showed suitable moisture content and viscosity and good solubility. The BCFA also helped reduce the number of folds on the surface of the milk powder particles. CONCLUSION: The findings of this study indicate that goat milk powders with BCFA exhibit differences in quality and microstructure in comparison with ordinary goat milk powder, which is relevant for the future development and application of BCFA in foods. © 2022 Society of Chemical Industry.

Storage Quality Variation of Mushrooms (Flammulina velutipes) after Cold Plasma Treatment.

Flammulina velutipes is susceptible to mechanical damage, water loss, microbial growth, and other factors that lead to postharvest deterioration, thereby shortening the storage period. The purpose of this study was to analyze the effects of cold plasma treatment on the physicochemical properties and antioxidant capacity of F. velutipes during storage at 4 °C for 21 days. Compared to the control group, cold plasma cold sterilization (CPCS) treatment (150 Hz, 95 kV for 150 s) effectively inhibited the growth and multiplication of microorganisms on the surface of F. velutipes, with no significant effect on the fresh weight change and the superoxide anion generation rate, but with a higher postharvest 1,1-dephenyl-2-picrylhydrzyl (DPPH) clearance rate. Moreover, CPCS increased antioxidant enzyme activities, delayed both malondialdehyde (MDA) accumulation and vitamin C loss, inhibited the browning reaction and polyphenol oxidases (PPO) activity and protected F. velutipes cell membrane from disruption. In general, CPCS not only achieved bacteriostatic effects on F. velutipes during storage, but also reduced cell damage from free radical oxidation, resulting in better postharvest quality and longer shelf life.

Effect of blend oil on the volatile aroma profile and storage quality of garlic paste.

The aim of this study was to evaluate the effect of edible oil on the volatile aroma profile and storage quality of garlic paste, and to explore the underlying mechanisms. The administration of blend oil at 40 °C in a garlic to oil ratio of 1.8 had a higher overall acceptance by affective sensory test. Compared with the original garlic paste, the sensory aroma profile of the oil-immersed garlic paste was characterized by suppressed pungency, garlic scent and garlic odor, and enhanced oil scent. SPME-GC-MS and HS-GC-IMS showed that the application of blend oil caused great changes in the level of some compounds, which could explain its role in the oil-immersed garlic paste. Furthermore, the blend oil also reduced the growth rate of the total number of colonies and browning intensity, and inhibited the loss of allicin. Therefore, the application of blend oil in garlic paste improved the sensory aroma and delayed the deterioration of the product quality.

Effects of salicylic acid treatment on fruit quality and wax composition of blueberry (Vaccinium virgatum Ait).

The cuticular wax layer in fruit is a hydrophobic barrier which protects fruit from biotic and abiotic stress. The cuticular wax also affect fruit quality. This paper investigated the effects of salicylic acid on fruit quality and the cuticular wax in blueberry fruit during storage at room temperature (25 °C). 'Powderblue' blueberries (Vaccinium virgatum Ait) were treated with 1.0 mmol L-1 salicylic acid. The composition of cuticular wax layer and structure of epicuticular wax layer were analyzed at 4 d intervals during storage. Salicylic acid could efficiently delay the reduction of total wax content and affected the proportions of its constituents, including triterpenoids, esters, sterols, fatty acids, alcohols and alkanes. Our results also showed that there was no significant difference on the structure of epicuticular wax in salicylic acid treated fruits compared with that of the control. Salicylic acid delayed deterioration of blueberry fruit and enhanced its resistance to disease during storage.

Effects of 1-MCP treatment on sprouting and preservation of ginger rhizomes during storage at room temperature.

The purpose of this study was to explore the effects of 1-MCP on the sprouting and preservation of ginger rhizomes during storage at room temperature. Ginger rhizomes were treated with 1 µL L-1 1-methylcyclopropene (1-MCP) and stored at 23 ± 0.2 °C. Our data showed that application of 1-MCP reduced the rate of sprouting during storage compared with the control rhizome. Respiration rate and the reducing sugar content were also reduced following 1-MCP treatment, while the starch content increased. 1-MCP treatment increased the total phenol content and inhibited polyphenol oxidase (PPO) activity. 1-MCP treatment was also associated with a higher ascorbic acid content but a reduced crude fiber content. The generation of superoxide anion free radicals (O2-), hydrogen peroxide (H2O2) and malondialdehyde (MDA) was lower following 1-MCP treatment, while the activities of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) were higher compared with the controls. These results suggested that application of 1-MCP could reduce sprouting rates, decrease the accumulation of ROS, and maintain the quality of ginger rhizomes during storage at room temperature. It would be useful to further explore the role and mechanisms of action of ethylene in regulating the sprouting of ginger rhizomes.

Dog food production using curcumin as antioxidant: effects of intake on animal growth, health and feed conservation.

The objectives of this study were to produce dog food containing curcumin replacing synthetic antioxidants, to evaluate its beneficial effects on animal growth and health. Curcumin (100 mg/kg) was added after the extrusion process along with the other micronutrients. The final concentration of curcumin was 32.9 mg/kg. The control feed was composed of the same ingredients without curcumin. After a storage of 6 months, feed composition and pH did not differ; however, the feed with curcumin showed lower protein oxidation, lipid peroxidation and higher total antioxidant capacity. After 2 months of feed production, 12 young Beagle dogs received either curcumin-containing food (n = 6)  or the control diet (n = 6). The animals were fed twice a day using individual kennels. Blood samples were taken on d 1, 35 and 42. During the first 30 d of the study, the animals had natural infectious diseases that were controlled with anti-protozoals and antibiotics. Greater numbers of red blood cells were observed in dogs fed with curcumin (d 35 and 45), and there were greater numbers of white blood cells as a consequence of increased neutrophils on d 42. At the end of the experiment, a significant reduction in the number of lymphocytes was observed in dogs that ingested curcumin (d 42), suggesting an anti-inflammatory effect, manifested as a decrease in globulin levels. In the final 15 d of the experiment, the animals were clinical healthy. Higher serum levels of glucose, urea, triglycerides and cholesterol were observed in dogs fed with curcumin. Curcumin increased the activity of several antioxidant enzymes in addition to non-protein thiols and the total antioxidant capacity in the serum, consequently reducing levels of oxygen reactive species. Curcumin supplementation of dogs did not favour growth or weight gain. Neverthless, it was concluded that curcumin improved animal health, with emphasis on the stimulation of the antioxidant system and evidence of an anti-inflammatory effect.

Effect of ultrasonic treatment combined with 1-methylcyclopropene (1-MCP) on storage quality and ethylene receptors gene expression in harvested apple fruit.

The objective of our study was to investigate the effectiveness of ultrasonic treatment combined with 1-methylcyclopropene (1-MCP) on storage quality and gene expression of postharvest apples compared with ultrasonic or 1-MCP treatment alone. Ethylene production, respiratory rate, firmness, soluble solid content (SSC), peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) activity, and ethylene receptors gene expression of apples were tested. The results indicated 1-MCP or ultrasonic treatment-restrained ethylene production and respiratory rate, improved firmness, suppressed the escalation of SSC, enhanced the activities of POD, SOD, and CAT, suppressed the gene expression level of MdETR1 and MdERS1 compared with the untreated samples. Furthermore, effect of the combination was more observable than that of ultrasonic or 1-MCP alone. In a word, the results proved the technology of ultrasonic plus 1-MCP was effective to enhance the storage quality and lengthen the life span of apples. PRACTICAL APPLICATIONS: Jonah king apple has the characteristics of crisp texture, long shelf life, high sugar content, and solidity-acid ratio, which is suitable for the taste of east and southeast Asian. However, as for a kind of respiration climacteric fruit, the commercial quality of Jonah king apple dramatically drops during the later stage of storage due to its softening, superficial scald, and perishability. One of the primary problems in apple preservation is the reduction of microbial growth, which directly affects the internal quality of apple fruit. The aim of present work is to estimate the effect of ultrasonic plus 1-MCP treatment on storage quality and life span of apple fruit, as well as to provide theoretical basis to enhance the storage quality and lengthen the life span of apples.

Performance of mechanically deboned chicken meat protein coatings containing thyme or clove essential oil for storage quality improvement of beef sucuks.

The performance of mechanically deboned chicken meat protein (MDCM-P) coatings containing thyme (TEO) or clove essential oils (CEO) was investigated to improve the storage quality of heat treated sucuks during 45 days of storage at 4 °C. The sucuk slices were divided to 4 groups as uncoated, coated with MDCM-P solution, coated with MDCM-P solution containing 1.5% TEO and MDCM-P solution containing 1.5% CEO. Physical, chemical and microbial properties of sucuk samples were analyzed on 0, 15, 30 and 45 days of storage. Results indicated that the weight loss, pH, thiobarbituric acid reactive subtances, total viable and psychrotrophic bacteria counts increased, while a* and b* values and water activity decreased with storage time (p < .05). In all analysis periods, these changes were slowed down with coating applications containing essential oils, but the slowest changes were observed in coated sucuks with MDCM-P solution containing 1.5% CEO. Therefore, MDCM-P coatings containing CEO could improve the storage quality of heat treated sucuks at refrigerator.

Transient heat stress during tuber development alters post-harvest carbohydrate composition and decreases processing quality of chipping potatoes.

BACKGROUND: Adverse air and soil temperatures are abiotic stresses that occur frequently and vary widely in duration and magnitude. Heat stress limits productivity of cool-weather crops such as potato (Solanum tuberosum) and may degrade crop quality. Stem-end chip defect is a localized discoloration of potato chips that adversely affects finished chip quality. The causes of stem-end chip defects are poorly understood. RESULTS: Chipping potatoes were grown under controlled environmental conditions to test the hypothesis that stem-end chip defect is caused by transient heat stress during the growing season. Heat stress periods with 35 °C days and 29 °C nights were imposed approximately 3 months after planting and lasted for 3, 7 or 14 days. At harvest and after 1, 2 and 3 months of storage at 13 °C, potato tubers were evaluated for glucose, fructose, sucrose and dry matter contents at the basal and apical ends. Chips were fried and rated for defects at the same sampling times. Differences in responses to heat stress were observed among four varieties of chipping potatoes. Heat stress periods of 7 and 14 days increased reducing sugar content in the tuber basal and apical ends, decreased dry matter content, and increased the severity of stem-end chip defects. CONCLUSION: Transient heat stress during the growing season decreased post-harvest chipping potato quality. Tuber reducing sugars and stem-end chip defects increased while dry matter content decreased. Planting varieties with tolerance to transient heat stress may be an effective way to mitigate these detrimental effects on chipping potato quality. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Effects of curcumin-based photodynamic treatment on the storage quality of fresh-cut apples.

Photodynamic treatment (PDT) is an innovative technology with non-thermal and environmentally sound merits, but the evaluation on the storage qualities of fresh produce was scarce. In this study, the effects of curcumin-based PDT on the quality of fresh-cut 'Fuji' apple slices during storage at 4 °C were investigated. The impacts on the survival of Escherichia coli, color and weight loss were examined under different curcumin concentrations, illumination time or incubation time. Curcumin-based photodynamic inactivation of E. coli on the surface of apple slices reached 0.95 log. Curcumin-based PDT was proven to prevent browning and weight loss. Additionally, PDT significantly reduced the activity of polyphenol oxidase and peroxidases to 48% and 51%, respectively. Moreover, there were few negative changes in total phenolic, ascorbic acid content and anti-oxidant activity of the treated apples. These results indicated that curcumin-based PDT was a viable and promising non-thermal technology to preserve the quality of fresh produce.

Comparative proteomics analysis reveals the effect of germination and selenium enrichment on the quality of brown rice during storage.

Selenium (Se) can delay the quality deterioration of rice during storage, however, the mechanisms remain unclear. In this study, changes in the quality of brown rice, germinated brown rice, and selenized germinated brown rice stored at 38 °C and 90% relative humidity with various vacuum levels for 120 or 150 days were investigated. Fatty acid value and carbonyl value were determined every 30 days. Comparative proteomics technology was applied to determine the mechanisms of germination and Se enrichment on the storage quality of rice. Approximately 142 abundance changed proteins were found, of which 37 proteins were identified. By functional classification, proteins involved in processes of carbohydrate metabolism, lipid metabolism, oxidation-reduction, and protein catabolism may contribute to the different storage qualities of three samples. This study provides novel insights into Se response in rice at the proteome level, which are expected to be beneficial for exploring Se response tracts in rice.

Preservative effect of Asparagus racemosus: A novel additive for bioactive edible films for improved lipid oxidative stability and storage quality of meat products.

Asparagus racemosus was used as a bioactive ingredient for the development of a novel calcium alginate edible film with preservative potential for improved lipid oxidative stability and storage quality of meat products. Chevon sausages were used as a model system and were aerobically packaged in the edible films incorporated with A. racemosus viz. T0 (0.0%), T1 (1.0%) and T2 (2.0%) and were stored under refrigerated (4 ±â€¯1 °C) conditions. Products packaged in T1 and T2 edible films exhibited significantly (P < 0.05) lower values for TBARS (mg malonaldehyde/kg), microbial counts (cfu/g) and FFA (% oleic acid) indicating the bioactive properties of the developed films. Significantly (P < 0.05) higher sensory scores were recorded for the products packaged in T1 and T2 films. A. racemosus added antioxidant and antimicrobial properties to the developed films which improved the lipid oxidative stability and storage quality of the model meat product.

Suppression of the vacuolar invertase gene delays senescent sweetening in chipping potatoes.

BACKGROUND: Potato chip processors require potato tubers that meet quality specifications for fried chip color, and color depends largely upon tuber sugar contents. At later times in storage, potatoes accumulate sucrose, glucose, and fructose. This developmental process, senescent sweetening, manifests as a blush of color near the center of the fried chip, becomes more severe with time, and limits the storage period. Vacuolar invertase (VInv) converts sucrose to glucose and fructose and is hypothesized to play a role in senescent sweetening. To test this hypothesis, senescent sweetening was quantified in multiple lines of potato with reduced VInv expression. RESULTS: Chip darkening from senescent sweetening was delayed by about 4 weeks for tubers with reduced VInv expression. A strong positive correlation between frequency of dark chips and tuber hexose content was observed. Tubers with reduced VInv expression had lower hexose to sucrose ratios than controls. CONCLUSION: VInv activity contributes to reducing sugar accumulation during senescent sweetening. Sucrose breakdown during frying may contribute to chip darkening. Suppressing VInv expression increases the storage period of the chipping potato crop, which is an important consideration, as potatoes with reduced VInv expression are entering commercial production in the USA. © 2017 Society of Chemical Industry.

Exogenous γ-aminobutyric acid treatment affects citrate and amino acid accumulation to improve fruit quality and storage performance of postharvest citrus fruit.

The loss of organic acids during postharvest storage is one of the major factors that reduces the fruit quality and economic value of citrus. Citrate is the most important organic acid in citrus fruits. Molecular evidence has proved that γ-aminobutyric acid (GABA) shunt plays a key role in citrate metabolism. Here, we investigated the effects of exogenous GABA treatment on citrate metabolism and storage quality of postharvest citrus fruit. The content of citrate was significantly increased, which was primarily attributed to the inhibition of the expression of glutamate decarboxylase (GAD). Amino acids, including glutamate, alanine, serine, aspartate and proline, were also increased. Moreover, GABA treatment decreased the fruit rot rate. The activities of antioxidant enzymes and the content of energy source ATP were affected by the treatment. Our results indicate that GABA treatment is a very effective approach for postharvest quality maintenance and improvement of storage performance in citrus production.

Effect of selenium enrichment on the quality of germinated brown rice during storage.

Changes in the quality of selenized germinated brown rice (Se-GBR) and germinated brown rice (GBR) under controlled temperature storage were investigated. Samples were sealed in air-tight jars (75% RH) and stored at 15, 25, or 35 °C for 9 months. Fatty acid value (FAV), peroxide value (POV), and carbonyl value (CV) were determined every 45d. FAV, POV, and CV gradually increased with the storage period. Samples stored under low-temperature showed lower FAVs, POVs, and CVs than samples stored at higher temperatures. Compared with GBR, Se-GBR showed lower FAVs, POVs and CVs; this indicates Se exerted a positive effect on the preservation of rice quality. Over 100 volatile compounds were identified, and 15 volatile aldehydes were further studied. To determine the distribution pattern of volatile aldehydes, principal component analysis (PCA) was employed. The first two principal components determined from the PCA of volatile aldehydes explained 50.22% of the variance observed.

Potential of carboxymethyl cellulose and γ-irradiation to maintain quality and control disease of peach fruit.

Carboxymethyl cellulose (CMC) coatings alone and in combination with gamma irradiation were tested for maintaining the storage quality and control of post-harvest gray and black mold disease of peach. Matured green peaches were CMC coated at levels 0.5-1.0% (w/v) and gamma irradiated at 1.2 kGy. The treated fruit including control was stored under ambient (temperature 25 ± 2°C, RH 70%) and refrigerated (temperature 3 ± 1°C, RH 80%) conditions. In fruits treated with individual treatments of 1.0% (w/v) CMC; 1.2 kGy irradiation and combination of 1.0% (w/v) CMC and 1.2 kGy irradiation, no decay was recorded up to 6, 8 and 14 days of ambient storage. Irradiation alone at 1.2 kGy prevented the onset of disease incidence up to 4 days compared to 2 days by 1.0% (w/v) CMC coating following 30 days of refrigeration. Combination of CMC at 1.0% (w/v) and 1.2 kGy irradiation prevented disease incidence of peach up to 7 days during post-refrigerated storage at 25 ± 2°C, RH 70% following 30 days of refrigeration. Above combinatory treatment can be of great potential in facilitating the marketing of the fruit, thereby benefiting the growers.