Early Stage Of Storage Research Articles

Effect of Chitosan/Gum Arabic Blends Enriched by Sodium Nitroprusside or Methyl Salicylate on the Storability and Antioxidant Activity of Tomato Fruit.

The impact of methyl salicylate (MeSA) or sodium nitroprusside (SNP) in chitosan (CS)/Gum Arabic (GA) mixture on physio-chemical characteristics and antioxidant status during the postharvest ripening of green tomato fruits was studied. CS/GA-MeSA at a 1 mM formulation was the best treatment to retard firmness and titratable acidity (TA) losses. Moreover, this formulation retarded pigmentation progress where it had the lowest significant values of total carotenes (TCs) and lycopene (LYP) contents until the 15th day of the storage period, as well as efficiently faced the rise in malondialdehyde (MDA) levels. Moreover, peroxidase (POD), polyphenol oxidase (PPO), catalase (CAT), and phenylalanine ammonia-lyase (PAL) activities of tomatoes treated with CS/GA-SNP at 2 mM were significantly better than that of control in the primary stages of storage. CS/GA-SNP at a 2 mM formulation showed an extremely high significant content of total polyphenol (TP) in the early stage of storage, while CS/GA and CS/GA-MeSA at 1 and 2 mM accumulated higher significant TP contents than uncoated fruits at the late stage of storage. All formulations were characterized by FTIR spectroscopy. Furthermore, the polymer formulations exhibited strong antifungal activity against Alternaria alternata and Botrytis cinerea as major pathogens of postharvest tomatoes. Transmission electron microscope (TEM) observations for the mycelia of both fungi treated by CS/GA-MeSA at 2 mM revealed serious ultrastructural damage, including distortion of the cell wall and cell membrane and degradation of cytoplasmic organelles.

Storage Temperature Affects the Accumulation of Phenolics in Fresh-Cut Melon by Accelerating the Sucrose Decomposition

To accurately evaluate the role of storage temperature in improving the quality of fresh-cut fruits and vegetables, the effects of two storage temperatures (5 °C and 15 °C) on the phenylpropanoid pathway and sucrose metabolism in fresh-cut melon (cv. Yugu) cubes were determined. A higher temperature (15 °C) expedited sucrose decomposition in the melon cubes at the early stage of storage, resulting in higher levels of glucose and fructose. This effect was corroborated by increased activities of acid invertase (AI), neutral invertase (NI), and sucrose synthase cleavage (SS-c), along with higher expressions of CmAI1/2, CmNI1/2, and CmSS1/2 in the melon cubes at 15 °C. Additionally, the higher activity and gene expression of hexokinase in melon cubes at 15 °C led to an increase in the utilization rate of sugars toward downstream metabolic pathways. Moreover, the melon cube storage at 15 °C elevated the activities and gene expressions of phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), and 4-coumaric acid: CoA ligase (4CL), thereby increasing the synthesis of phenolics. Sucrose showed a significant negative correlation with PAL, C4H, and 4CL, as well as with CmPAL5/7 and CmC4H1/3. However, hexokinase displayed a significant positive correlation with PAL, C4H, and 4CL, as well as with CmPAL1, CmPAL3-9, CmC4Hs, and Cm4CLs. These findings demonstrate that a higher-temperature storage of melon cubes can accelerate the phenylpropanoid pathway and sucrose metabolism by regulating the activity and gene expression of related enzymes, thereby inducing phenolic accumulation. These results also indicate that lower-temperature storage is not conducive to the conversion of sugars into phenolics in fresh-cut melon. Therefore, the temperature can be appropriately and briefly raised in the production and preservation process of fresh-cut melon to obtain higher levels of phenolics.

A Sustainable Material for Sheep's Cheese Wedges Stored under Different Atmosphere Conditions.

This study is based on the need to improve packaging sustainability in the food industry. Its aim was to assess the performance of a recyclable plastic material for semi-hard sheep's cheese wedges packaging as an alternative to conventional non-sustainable plastic materials. Four different packaging treatments (air, vacuum, and CO2/N2 gas mixtures 50/50 and 80/20% (v/v)) were studied. Changes in gas headspace composition, sensory properties, cheese gross composition, weight loss, pH, colour, and texture profile were investigated at 5 ± 1 °C storage for 56 days. The sensory analysis indicated that vacuum packaging scored the worst in paste appearance and holes, and air atmosphere the worst in flavour; it was concluded that cheeses were unfit from day 14-21 onwards. Air and vacuum packaging were responsible for most of the significant changes identified in the texture profile analysis, and most of these happened in the early stages of storage. The colour parameters a* and b* differentiated the air packaging from the rest of the conditions. As in previous studies using conventional plastic materials, modified atmosphere packaging, either CO2/N2 50/50 or 80/20% (v/v), was the most effective preserving technique to ensure the quality of this type of cheese when comparing air and vacuum packaging treatments.

Riboflavin alleviates the occurrence of anthracnose caused by Colletotrichum gloeosporioides in postharvest mango and the possible mechanisms involved

Colletotrichum gloeosporioides is a major pathogenic fungus that causes anthracnose in stored mangoes, and it exhibits higher pathogenicity compared to Colletotrichum acutatum. This study primarily investigates the mechanism by which riboflavin prevents mango anthracnose caused by Colletotrichum gloeosporioides. In vitro experiments demonstrated that a concentration of 1.0 mmol L−1 riboflavin exhibited a strong inhibitory effect on spore germination of Colletotrichum gloeosporioides strains isolated from different major mango-producing regions in China, surpassing the efficacy of the chemical agent pyrimethanil. Furthermore, mango fruits infected with Colletotrichum gloeosporioides and treated with 1.0 mmol L−1 riboflavin exhibited a significant reduction in disease index. The mechanism behind this is that riboflavin not only generated reactive oxygen species (ROS) but also induced the production of ROS in the fruit during the early stages of storage, directly killing Colletotrichum gloeosporioides. Additionally, riboflavin activated phenylalanine ammonia lyase (PAL) and peroxidase (POD), leading to the production of total phenols and lignin, enhancing the fruit's disease resistance. Riboflavin also increased the activity of β-1,3-glucanase (GLU) and chitinase (CHI), which can disrupt the cell wall of Colletotrichum gloeosporioides. Moreover, riboflavin enhanced the activity of superoxide dismutase (SOD) and catalase (CAT) in the fruit, reducing weight loss percentage and minimizing the degradation of total soluble solids (TSS). These findings highlight the efficacy of riboflavin in preventing and controlling mango anthracnose.

Lipidomics‐based study of lipid quality of fish by‐products: a case study of sea bass (Lateolabrax japonicus)

SummaryBy‐products of sea bass are a good source of lipids, among which viscera was the best lipid source containing 66% total lipids. Acid value, peroxide value (POV), p‐anisidine value (p‐AV), and conjugated diene value (CDV) were used to monitor oxidation. Visceral oil has a relatively higher level of POV, AV and CDV than head and belly. Radical production detected by ESR spectroscopy was also high in viscera. Fatty acid analysis showed that visceral oil of sea bass has a very high ratio of monounsaturated fatty acid, which includes oleic acid (C18:1n9), and palmitoleic acid (C16:1n9) accounting for 28.45% and 3.25% of total visceral oil and are rich in omega‐6 polyunsaturated fatty acids accounting for 34.78% of total lipids. Volatile compounds in visceral oil were low with flora and spicy oil wax aroma. Low amounts of aldehydes, ketones and alcohols indicated a low level of oxidation in the early stage of storage. ESR results indicated higher free radical level in visceral oil, which might result in the Inside‐Out quality deterioration.

Structural analysis of platelet fragments and extracellular vesicles produced by apheresis platelets during storage

AbstractPlatelets (PLTs) for transfusion can be stored for up to 7 days at room temperature (RT). The quality of apheresis PLTs decreases over storage time, which affects PLT hemostatic functions. Here, we characterized the membranous particles produced by PLT storage lesion (PSLPs), including degranulated PLTs, PLT ghosts, membrane fragments, and extracellular membrane vesicles (PEVs). The PSLPs generated in apheresis platelet units were analyzed on days 1, 3, 5, and 7 of RT storage. A differential centrifugation and a sucrose density gradient were used to separate PSLP populations. PSLPs were characterized using scanning and transmission electron microscopy (EM), flow cytometry (FC), and nanoparticle tracking analysis (NTA). PSLPs have different morphologies and a broad size distribution; FC and NTA showed that the concentration of small and large PSLPs increases with storage time. The density gradient separated 3 PSLP populations: (1) degranulated PLTs, PLT ghosts, and large PLT fragments; (2) PEVs originated from PLT activation and organelles released by necrotic PLTs; and (3) PEV ghosts. Most PSLPs expressed phosphatidyl serine and induced thrombin generation in the plasma. PSLPs contained extracellular mitochondria and some had the autophagosome marker LC3. PSLPs encompass degranulated PLTs, PLT ghosts, large PLT fragments, large and dense PEVs, and low-density PEV ghosts. The activation-related PSLPs are released, particularly during early stage of storage (days 1-3), and the release of apoptosis- and necrosis-related PSLPs prevails after that. No elevation of LC3- and TOM20-positive PSLPs indicates that the increase of extracellular mitochondria during later-stage storage is not associated with PLT mitophagy.

The delaying effect of a novel polyethylene nanopackaging on postharvest stipe elongation of Flammulina velutipes and its mechanism analysis

The stipe elongation is a typical characteristic of quality deterioration of postharvest Flammulina velutipes. We explored the delaying effect of a novel polyethylene nanopackaging (PENP) on stipe elongation in F. velutipes during storage and the underlying mechanism. The changes in quality, physical and chemical properties, and gene expression of F. velutipes in PENP during 18-day storage at low temperature were analyzed by morphological observation and physiological, biochemical, and transcriptomic methods. The results showed that PENP treatment could reduce the respiration of F. velutipes by maintaining higher CO2 and lower O2 content, decrease the stipe elongation rate and keep the postharvest storage quality of F. velutipes. PENP also inhibited the increase in chitin and β-glucan content, the main components of the cell wall of F. velutipes, maintaining sufficient ATP content and energy charge (EC) values inside the stipe. Transcriptome analysis showed that PENP inhibited cell wall regeneration by down-regulating genes related to chitin degradation (Unigene0001917, Unigene0018811 and Unigene0007053) and β-glucan degradation (Unigene0010562 and Unigene0010561), thus delaying stipe elongation. During the early stage of storage, PENP also inhibited energy metabolism by down-regulating succinate dehydrogenase (SDH), cytochrome c oxidase (CCO), and F1F0-ATPase-related genes involved in the oxidative phosphorylation pathway. In summary, PENP delayed postharvest stipe elongation of F. velutipes by inhibiting the synthesis of chitin and glucan in the cell wall and maintaining low energy metabolism in the stipe cells during early storage.

Recent advances with cold plasma technology for millet processing: A brief review

AbstractAs a grain with high nutritional content and tolerance to extreme weather, millet has a potential food business. However, the processing is necessary to enhance the physical and nutritional quality of millet. Food products with minimal processing, improved sensorial and natural flavors, with no added chemicals to preserve them are in greater demand among customers. High‐quality product produced using green alternative processing techniques significantly evolved in the last two decades. Moreover, recent years see potential study of cold plasma technology in the food industry for increased functional attributes and energy efficiency. This review has been framed to describe the impact of cold plasma on the quality attributes of millet and millet products exploring cold plasma research on millet products, focusing on nutrition, anti‐nutrient reduction, structural, physicochemical, digestive, hydration, and functional properties. Furthermore, this work pursues to improve interventions by identifying the knowledge gaps in the processing of millet using cold plasma.Practical ApplicationsThe shelf life of the millet products is extended as a result of the plasma treatment, through the reduction in the moisture content. During the early stages of storage, millet flour is affected by rancidity, which is positively treated by plasma processing. The water absorption and swelling capacity of the treated millet sample have increased along with a rise in solubility. Therefore, the hydration and pasting abilities of millet improved, making it possible to utilize it in complementary food formulations as well as for the development of viscous foods.

Association of lipidome evolution with the corresponding volatile characteristics of postmortem lamb during chilled storage

This investigation aims to elucidate the roles of lipids on the volatilome evolution of postmortem lamb and its possible modulated mechanism behind. Firstly, the physicochemical properties were evaluated as coordinating role of flavor quality, and results suggested that chilled storage improved tenderness of muscle tissue and induced color variation of lamb. According to multivariate results, the pattern shifts of volatile profile of chilled lamb could be differentiated successfully. Besides, the potential differential aroma-active compounds were identified, including up-regulated heptanol, 1-octen-3-ol, 6-methyl-2-heptanone, 3-heptanone, 2-pentyl furan and octanol in early stage of storage (days 0–3) and down-regulated hexanal, pentanal, hexanol, octanol, 6-methy-2-heptanone, heptanol, 1-octen-3-ol and benzaldehyde in later stage of storage (days 3–7). Then, discriminant analysis recognized the differential lipid species corresponding to different stages of lamb flavor development, involving phospholipids, sphingolipids, glycerolipids and fatty acyls. Herein, the degradation of acyl carnitine and diglyceride may be an important pathway that contributed to volatilome evolution of postmortem lamb in the early stage of storage. These results demonstrated a potential relationship between headspace volatilome and lipidome evolutions, providing a comprehensive understanding for development of lipid-derived volatile compounds of chilled lamb and useful for lamb characteristic flavor quality evaluation and control in future.

Effects of Volatile Flavour Compound Variations on the Varying Aroma of Mangoes 'Tainong' and 'Hongyu' during Storage.

The aroma, taste, and flavour profiles of mango cultivars vary, directly influencing their marketability and consumer acceptance. In this study, we explored the effects of volatile organic compounds (VOCs) on the distinct aromas of two mango cultivars during storage using GC-IMS and HS-SPME-GC-MS combined with OPLS-DA analysis. Our findings revealed that the terpene and aldehyde contents were higher in the 'Tainong' mango cultivar, compared to the 'Hongyu' mango, while the ester content was lower. The aroma was attributed to the presence of terpinolene, 2-nonenal, delta-carene, and alpha-phellandrene in the early stages of storage, and later-between 5 and 11 days-to ethyl acetate, ethyl butyrate, and ethyl propanoate. Further analysis of characteristic VOCs using OPLS-DA demonstrated and explained the strong grassy aroma of the 'Tainong' mango, and the strong fruity and sweet aromas of the 'Hongyu' mango. Additionally, esters mainly accumulated during the later periods of storage, especially propyl butyrate, which was produced and accumulated when fruit quality deteriorated in the later storage period. Our study provides a theoretical basis for detecting mango VOCs during storage to determine the appropriate marketing time for the two mango cultivars and enables informed consumer choice.

Evaluation of Preharvest Melatonin on Soft Rot and Quality of Kiwifruit Based on Principal Component Analysis.

Botryosphaeria dothidea is the source of the deadly kiwifruit disease known as soft rot. In order to explore the role of melatonin in regulating the postharvest quality and disease resistance of kiwifruit at different growth and development stages, in this study, we applied melatonin at different concentrations to kiwifruit at the young fruit, expansion, and late expansion stages to assess its effect on fruit resistance to B. dothidea, minimize soft rot, and maintain postharvest fruit quality. The results showed that melatonin significantly suppressed the mycelial growth of B. dothidea, with 1.0 mmol/L melatonin inhibiting it by up to 50%. However, 0.1-0.3 mmol/L melatonin had the best control over soft rot. Furthermore, spraying MT during kiwifruit growth can successfully increase fruit weight; preserve postharvest fruit firmness; reduce respiration intensity in the early stages of storage; delay the rise in soluble solids, while maintaining a high titratable acid content to ensure suitable solid acid ratio; increase total phenol, flavonoid, chlorophyll, carotenoid, and ascorbic acid contents; and delay the rise in soluble sugar contents in the late stages of storage. These results have a positive effect on maintaining the nutritional composition of kiwifruit. However, the effects on weight loss, dry matter content, and soluble protein content were not significant. In addition, the results of the principal component analysis demonstrated that 0.3 mmol/L MT increased kiwifruit's resistance to soft rot while preserving postharvest fruit quality.

Ethanol fermentation- and ethylene physiology-related gene expression profiles in Red Delicious apples stored under variable hypoxic conditions and protocols

Dynamic Controlled Atmosphere (DCA) is beneficial in maintaining specific quality parameters but, due to the extreme oxygen levels applied, can cause adverse effects on the fruit by inducing excessive anaerobic metabolism and the production of off-flavors. The metabolic adaptation and responses of apples (Malus domestica Borkh.) cv. Red Delicious to static or dynamic oxygen concentrations (0.3 and 0.8%, with sequential shifts) during cold storage for 7 months were studied by monitoring quality parameters and the expression of genes involved in sugar, fermentative metabolism, and ethylene physiology. Ethanol content reached the highest levels (around 400 mg/kg FW) under 0.3% oxygen concentration and fruit firmness appeared to be reduced in samples accumulating the highest levels of ethanol. Oxygen switch was effective in reducing the ethanol concentrations with timing-dependent variable effects. The expression of fermentative (alcohol dehydrogenase, lactate dehydrogenase, pyruvate decarboxylase) and sugar metabolism (β-amylase; phosphofructokinase; sucrose synthase) genes resulted to be differently affected by the hypoxic conditions imposed, in particular during the early stages of storage. Sucrose synthase expression appeared to be highly sensitive to changes in low oxygen concentration. Ethylene biosynthesis (ACC synthase and oxidase) genes showed marked differences in their expression in relation to the static and dynamic protocols and the hypoxic conditions, as well as six Ethylene Responsive Factors (ERF) genes, some of them possibly involved in the oxygen sensing mechanism operating in fruit tissues.

Cut-Wounding Promotes Phenolic Accumulation in Cucumis melo L. Fruit (cv. Yugu) by Regulating Sucrose Metabolism

The effect of cutting on the molecular changes underlying sucrose metabolism and the phenylpropanoid pathway in melon fruit (cv. Yugu) during storage at 15 °C was investigated. Furthermore, the key metabolites, enzymes, and genes involved in sucrose and phenylpropanoid metabolism were determined. Results showed that the cutting of melon increased the activities of acid invertase (AI), neutral invertase (NI), and sucrose synthase-cleavage (SS-c) and the expressions of CmAI1/2, CmNI1/2, and CmSS1, while sucrose synthase-synthesis (SS-s) and sucrose phosphate synthase (SPS) activities and the CmSS2/3 and CmSPS1/2/4 gene expressions were suppressed. These led to sucrose decomposition and fructose and glucose accumulation in fresh-cut melon at the early stage of storage. Moreover, cutting increased the activity and gene expression of hexokinase, which accelerated the transformation of hexose in fresh-cut melon. In addition, cutting enhanced the activities of phenylalanine ammonia lyase (PAL), cinnamate-4-hydroxylase (C4H), and 4-coumarate-CoA ligase (4CL) and up-regulated the expressions of CmPAL1-9, CmC4H1-4, and Cm4CL1/2/3, which activated phenylpropanoid metabolism and resulted in phenolic accumulation in fresh-cut melon. These findings demonstrate that cutting of melon can enhance sucrose metabolism and phenylpropanoid pathway by regulating the activities and gene expressions of related enzymes. Therefore, cut-wounding promoted the conversion of sugars to supply the necessary substrates for phenolic accumulation in fresh-cut melon.

Comparative analysis of the nitrogen monoxide content and optical-morphometric characteristics of erythrocyte-containing blood components during storage

Flow cytometry was used to analyze the content of intracellular nitrogen monoxide in erythrocyte-containing blood components during blood storage with hemopreservative for 4 weeks. It was found that storing of blood is accompanied by increased levels of intracellular nitrogen monoxide in erythrocytes and thus by a change in optical and morphometric parameters of red blood cells. In the early stages of storage, erythrocytes were represented by discocytes, and during long storage erythrocytes became more spherical (spherocytes) as the percentage of microcytes that accumulated nitrogen monoxide increased and their intracellular hemoglobin levels were decreased.

A power analysis for detecting aging of dry‐stored soybean seeds: Germination versus RNA integrity assessments

AbstractDeterioration of seed during dry storage is a major problem for genebanks and seed companies. Germination tests are the gold standard to monitor seed viability; however, these prove to be insensitive during the early stage of storage when viability changes are subtle. Recent findings demonstrate that decline in RNA integrity may be an early indicator of seed longevity during dry storage. The goal of this study was to determine the sensitivity of RNA integrity, measured as RNA integrity number (RIN), regarding how soon changes can be detected and how many seeds are required. We compared the statistical power of germination and RIN assays using a well‐characterized collection of ‘Williams 82’ soybean seeds, with cohorts harvested between 1989 and 2019 and stored at 5 °C. Germination was monitored in 1‐ to 3‐yr intervals since 1989, and RIN was monitored in 1‐ to 2‐yr intervals since 2016 providing an extensive dataset to conduct statistical power analyses. Decline in RIN can be detected in soybean seeds within 10 yr with a RNA monitor test that consumes approximately 30 seeds. In contrast, a germination test detects deterioration in 16 yr using approximately 50 seeds, and by this time, the seed lot is near the limit of longevity and has entered the phase of rapid mortality. Work from this study indicates that early detection of aging using RIN decline can be used to predict the longevity threshold to optimize viability monitoring and regeneration times, preventing loss of valuable samples by overtesting or missing the longevity threshold.

Assessment of order of helical structures of retrograded starch by Raman spectroscopy

In this study, the long- and short-range order of retrograded starch was evaluated using Fourier-transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (XRD), and Raman spectroscopy. FTIR and XRD could not assess the degree of order of various helical structures. Raman spectroscopy was used to establish a method for evaluating the order of the helical structures of the retrograded starch. The characteristic peaks of the Raman bands around 865, 1343, and 2908 cm −1 were related to the amylose double helix, amylose single helix, and amylopectin double helix, respectively. The full width at half maximum (FWHM) of the characteristic peaks was used to assess the order of the helical structure. During retrogradation, the order of all helical structures increased, which was greater for the amylose double helix than that of other helical structures in the early stage of storage. The crystallization rate of the amylose double helix was also higher than that of other helical structures. • A method for assessing the order of helical structures was established. • The order of all helical structures increased during starch retrogradation. • Crystallization rate of various helical structures were obtained.

Study on the quality change of crown pear during storage

Using the high-quality Crown Pear as the subject of experimental research, an analysis of the changes in the quality of Crown Pears during a storage period is conducted to provide a theoretical basis for the development of the pear cold storage industry. The study utilizes a handheld digital refractometer, texture analyzer, colorimeter, T-type thermocouple, and electronic balance to explore six aspects of Crown Pears: soluble solids content, hardness, color difference, freezing point, drying loss, and taste. The results reveal the following changes in pear quality during different storage periods within one cycle: the content of soluble solids in Crown Pears initially increases and then decreases during the storage period; hardness decreases with increasing storage time; the external appearance of pears gradually darkens; and drying loss increases with storage time. During the cold storage process of Crown Pears, the optimal temperature setting for the cold storage should be maintained at -1°C to 0.5°C. The flavor of Crown Pears is not optimal during the early stage of storage. The storage time for Crown Pears should be within four months.

Control Efficacy of Salicylic Acid Microcapsules against Postharvest Blue Mold in Apple Fruit.

Salicylic acid (SA) is a natural inducer of disease resistance in fruit, but its application in the food industry is limited due to low water solubility. Here, SA was encapsulated in β-cyclodextrin (β-CD) via the host-guest inclusion complexation method, and the efficacy of SA microcapsules (SAM) against blue mold caused by Penicillium expansum in postharvest apple fruit was elucidated. It was observed that SAM was the most effective in inhibiting the mycelial growth of P. expansum in vitro. SAM was also superior to SA for control of blue mold under in vivo conditions. Enzyme activity analysis revealed that both SA and SAM enhanced the activities of superoxide dismutase (SOD) and phenylalanine ammonia lyase (PAL) in apple fruit, whereas SAM led to higher SOD activities than SA. Total phenolic contents in the SAM group were higher than those in the SA group at the early stage of storage. SAM also improved fruit quality by retarding firmness loss and maintaining higher total soluble solids (TSS) contents. These findings indicate that microcapsules can serve as a promising formulation to load SA for increasing P. expansum inhibition activity and improving quality attributes in apple fruit.

Changes in odorants and flavor profile of heat-processed beef flavor during storage.

Flavor quality changes of heat-processed beef flavor (HPBF) upon storage are greatly affected by storage conditions. Flavor characterization of HPBF stored for 168 days resulted in 17 key odor-active compounds having flavor dilution factors log3 FD ≥ 3 and odor activity values >1. Based on the concentration changes of these key odorants, a total of 13 HPBF samples were divided into four groups by hierarchical cluster analysis. Combined with flavor profile analysis, the overall flavor of HPBF gradually changed from a characteristic beef aroma to burnt and fermented soybean paste-like notes. Some of the 17 key odorants, such as 2-methyl-3-furanthiol, 2-furfurylthiol, methyl furfuryl disulfide, and difurfuryl disulfide, contributed to the characteristic beef aroma of the freshly prepared product and in the early stage of storage. On the other hand, the odor-active compounds 2-methylbutanal, dimethyl disulfide, dimethyl trisulfide, and 2-ethyl-3,5-dimethylpyrazine were associated with the later stage of storage showing a positive correlation with the intensity of burnt and fermented soybean paste-like notes. A molecular understanding of flavor profile changes of HPBF during storage will provide the basis for developing characteristic beef aroma notes and maintaining the keeping quality of beef products upon storage. PRACTICAL APPLICATION: The relationship between sensory quality and changes in odorant concentration of heat-processed beef flavor during storage will provide the molecular basis for developing high-quality thermal reaction meat flavorings.

Integrative metabolomics and transcriptomics analyses reveal pivotal regulatory mechanisms of 1-methylcyclopropene in maintaining postharvest storage quality of ‘Fuji’ apples

Abstract In this study, integrative metabolomics and transcriptomics analyses were conducted to investigate the effects of 1-methylcyclopropene (1-MCP) on apple fruit quality during long-term cold storage. The results showed that 1-MCP (1 μL/L) treatment could maintain fruits apparent quality (i.e. external color and firmness), inhibit the increase of rot rate and soluble solids content/titratable acidity ratio, decrease ethylene release, and respiratory intensity during cold storage, and extend shelf life. Moreover, 1-MCP had long-term effects on the accumulation of many qualities related to metabolite and gene expression in fruits. 1-MCP affected genes related to metabolism at the early stage of storage, specifically those of the glycolysis and tricarboxylic acid cycle pathways. Genes related to the degradation of sucrose, starch, and cellulose were inhibited, and some starch and cellulose synthesis genes were up-regulated by 1-MCP. Apart from ethylene synthesis and signal transduction being inhibited by 1-MCP, several enzymes (pectinesterase, pectate lyase, polygalacturonase) were involved in pectin degradation, and degradation products of the cell wall (i.e. d-galacturonic acid and d-glucuronic acid) were also strongly inhibited, further maintaining fruit firmness. Cysteine, as precursor glutathione (GSH) related to plant resistance, up-regulated the synthase gene. However, the expression of genes related to cyanoalanine synthase and amino acid utilization pathways was suppressed by 1-MCP. Collectively, 1-MCP could maintain the postharvest quality of apple fruits.