Postharvest Technology Innovation Center

Microgreens are young and tender leafy vegetables that have gained wider consumer acceptance. This is attributed to their low caloric composition and rich micronutrient and antioxidant composition. The present study investigated the bioactive composition and proximate analysis of fourteen microgreens belonging to Brassicaceae, Fabaceae, Pedaliaceae, Polygonaceae, Convolvulaceae, and Malvaceae. All the microgreens showed low calories (20.22 to 53.43 kcal 100 g−1) and fat (0.15 to 0.66 g 100 g−1), whilst mung bean and lentil microgreens showed considerable amounts of carbohydrate (7.16 g 100 g−1) and protein (6.47 g 100 g−1), respectively. Lentil microgreens had the highest total chlorophyll (112.62 mg 100 g−1) and carotenoid (28.37 mg 100 g−1) contents, whilst buckwheat microgreens showed the highest total phenolic content (268.99 mg GAE 100 g−1) and DPPH• scavenging activity (90.83 mM TEAC g−1). The lentil microgreens also presented high ascorbic acid content (128.70 mg 100 g−1) along with broccoli, Chinese kale, purple radish, and red cabbage microgreens (79.11, 81.33, 82.58, and 89.49 mg 100 g−1, respectively). Anthocyanin content was only detected in purple radish (0.148 mg CGE 100 g−1) and red cabbage (0.246 mg CGE 100 g−1). The results provide basic information and highlight the benefits of utilizing genetic biodiversity to obtain microgreens with the desired nutrients and antioxidants.

Exposure of mature green “Takanotsume” chili fruit to blue and red light-emitting diodes (LEDs) was investigated. The red LED accelerated the red color development of chili as indicated by higher a* and chroma values, as well as lower hue angle and total chlorophyll compared to the blue LED and darkness (control). These were linked to increases in β-carotene, free-capsanthin, and total carotenoids. The carotenoid biosynthesis-related genes, lycopene-β-cyclase (Lcyb), β-carotene hydroxylase (CrtZ), and capsanthin/capsolubin synthase (Ccs), were up-regulated by the red LED after 2 days of the experiment. The blue LED was more effective in increasing the expression of the phytoene synthase (Psy) gene at day 1 of experiment. The total phenolic, vitamin C content, and antioxidant capacity were also higher in the blue LED-treated chili. Results suggest that the responses of each carotenoid-related gene to the light wavelengths and the accumulation of phytochemicals are specific characteristics of this chili cultivar.

Abstract At the present, the mechanism of chlorophyll degradation in response to ionizing irradiation in harvested fruits have not been examined. To understand the effect of electron beam (E-beam) irradiation on the chlorophyll degrading pathway in relation to chlorophyll degrading enzymes activity, reactive oxygen species (ROS) and antioxidant capacities of harvested mangoes stored at 13 °C for 16 days were studied. E-beam-treated fruit significantly suppressed the activities of chlorophyll degrading enzymes especially pheophytinase (PPH) and chlorophyll degrading peroxidase (Chl-POX) in the late stage of storage. This resulted in the chlorophyll content being maintained. However, E-beam irradiation did not affect the activities of chlorophyllase (Chlase) and magnesium de-chelatase (MD). The respiration rate, ethylene production, ROS accumulation (hydrogen peroxide [H 2 O 2 ] and superoxide radical [O − . 2 ]) immediately increased after E-beam treatment, following which they significantly decreased in comparison to the control. E-beam treatment enhanced the fruit’s antioxidant capacity by activating the activities of catalase (CAT) and ascorbate peroxidase (APX) and glutathione (GSH) content, and inactivated the activity of superoxide dismutase (SOD). Further, it did not affect the activity of glutathione reductase (GR) and glutathione disulfide (GSSG), vitamin C content, or total phenolic content. These results imply that E-beam treatment has the potential to delay chlorophyll degradation by suppressing the Chl-POX and PPH activities as well as reduce ROS production via CAT, APX, and SOD activities and GSH content.

Microbial activity and browning were minimized and fresh-cut rose apple quality was maintained using sodium chlorite (SC) combined with calcium chloride (CC) and calcium ascorbate (CaAs) and by investigating the optimal concentration and dipping time of SC for inhibiting microbial activity and browning. Fresh-cut rose apple samples were dipped in SC solution at 100 mg/L and 200 mg/L for 1 min and 3 min, with filtered water and non-dipped samples as controls. All samples were kept at 4 ± 2 °C for 9 d. The results showed that 200 mg/L SC for 3 min was the best treatment to inhibit microbial growth (total bacteria, yeast and molds, Escherichia coli and coliforms), delay browning and polyphenol oxidase (PPO) activity of fresh-cut rose apples, but could not maintain the fresh firmness. A firmness experiment was conducted by dipping fresh-cut rose apples in 200 mg/L SC and in 200 mg/L SC combined with 20 g/L CC and 20 g/L CaAs (SC + CC + CaAs) for 3 min before storage at 4 ± 2 °C for 9 d. Samples immersed in filtered water were used as the control. The combined treatment delayed microbial contamination and browning by reducing the PPO activity and the accumulation of phenolic content, and maintained the fresh firmness of fresh-cut rose apples. Thus, the combination treatment of SC + CC + CaAs solution can protect fresh-cut rose apples against microbial contamination and delay browning and maintain firmness.

Ripe durian fruits produce unique volatiles of pungent odor comprising esters, alcohols, ketones, and sulfur-containing compounds. Recently, “Chanthaburi 1” hybrid bred from 2 famous commercial cultivars of “Chanee” and “Monthong” claimed to be less fragrant during ripening, but there was no report. The present study compared the volatile profiles from 3 Thai commercial cultivars of “Kanyao,” “Chanee,” and “Monthong” compared to “Chanthaburi 1”, and the relationships of the cultivars were organized using the volatile fingerprints. Out of 41 volatile compounds detected by SPME/GC-MS in ripe durian flesh, 33 compounds were esters, but only 14 esters were found in “Chanthaburi 1.” Ripe flesh of most durian cultivars contains ethyl-2-methyl butanoate and ethyl hexanoate as the active volatiles. “Chanthaburi 1” contained fewer components with low odor activity value (OAV) of the volatiles. “Chanee” ripe flesh exhibited the strongest durian smell among the four varieties, whereas “Monthong” exhibited a strong apple-like fruity odor and “Kanyao” was more green fruity. Diethyl disulfide and 3, 5 dimethyl-1, 2, 4-trithiolane contributing pungent smells of garlic or onion were found only in “Chanthaburi 1” and “Monthong.” In terms of detected volatiles, “Kanyao” and “Chanee” were highly close when “Monthong” was apart. PCA analysis revealed that “Chanthaburi 1” contained ester compounds ancestrally related to the parents, “Chanee” in the component I and “Monthong” in the component II. These data could be beneficial for managing the status of Thai durians in global markets.

Physico-chemical and quality changes in 72 sugar apple (Annona squamosa Linn.) fruits subjected to pre-harvest drought stress were analyzed at harvest and during storage at 10 °C or 15 °C, with 90–95% relative humidity. At harvest, the ascorbic acid, sugar and endogenous abscisic acid concentrations increased while the concentration of the substrate indicating a 50% loss in 2,2-diphenyl-2-picrylhydrazyl scavenging activity (DPPH EC50) decreased in fruit from drought-treated trees compared with fruit from well-watered trees (control). The fresh weight loss of fruit stored at 15 °C was higher than at 10 °C, with no significant effect of drought treatment. In contrast, fruit firmness was reduced by drought treatment compared with the control during storage at both temperatures. Respiration, ethylene production and the endogenous abscisic acid and total sugar concentrations were higher in fruit from the drought-treated trees kept at 15 °C. The total ascorbic acid concentration was higher in fruit from drought-stressed trees kept at 10 °C compared with other treatments. This was concomitant with the DPPH EC50 value, which was lowest in fruit from drought-stressed trees stored at 10 °C. These results implied that pre-harvest drought stress treatment activated antioxidant activity and increased sugar concentration in sugar apple fruit. In addition, pre-harvest drought stress hastened fruit ripening. Thus, based on the results, storage of sugar apple fruit at 10 °C is recommended as this induces antioxidant activity which delays chilling injury for 8 d.

Impact of hydropriming on germination and seedling establishment of sunflower seeds at elevated temperature | Rose Catiempo, Songsin Photchanachai, Emma Ruth Bayogan, Chalermchai Wongs-Aree | Agricultural Journals

Utilizing organic waste to sustain agricultural productivity poses a global challenge. Increasing soil organic carbon through compost-biochar pellets emerges as a promising strategy for sustainable agricultural productivity. Therefore, the objective of this study was to produce soil amendment pellets (SAPs) using various mixtures of compost (cow dung, Albizia saman leaves, Dipterocarpus alatus leaves, and mixed leaves), water (20%, 30%, and 40% by weight), and biochar (0%, 5%, and 10% by weight). When consider individual factor, the results indicate that composted mixed leaves, characterized by small particles and high density, 5% by weight of biochar, and 20% by weight of water significantly improved both the production efficiency and properties of SAPs. An optimal combination effect is observed with A. saman leaves compost, 20% water content, and 5% biochar content. This combination resulted in the highest pelletization rate (244.80 kg hr-1), minimized energy consumption (13.45 kW-hr ton-1), and achieved the highest bulk density (933.33 kg m-3), approximately 2 times increase. When applied to soil, SAPs are viable for ensuring nutrient availability and carbon retention. Moreover, it leads to profound alterations in microbial activity and soil texture. Especially in SAPs, mixing with biochar facilitates the slow release of nutrients. In conclusion, this study demonstrates the successful production of SAPs, offering potential for the organic pelleting industry and highlighting their effectiveness in enhancing soil properties, thus promoting sustainable agriculture.

Banana blossoms are rich in fiber and nutrients and are a popular plant-based, vegan alternative to fish. However undesirable browning, usually visible at the peduncle cut-end, negatively impacts consumer acceptability of banana blossoms. The aim of this work was to develop safe alternatives to prevent browning in banana blossoms. First, the activities of primary enzymes associated with tissue browning, i.e., polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia lyase (PAL), were assayed. Our data showed that PPO and POD were the key enzymes responsible for blossom browning as they increased in activity, reaching a maximum at pH 7, as browning developed. In contrast, PAL activity decreased, and total phenolic content did not change as browning progressed, indicating PAL was not induced by cutting and may not be involved in blossom browning. Second, to find antibrowning agents for banana blossoms that can substitute for the use of sodium metabisulfite (SMS), different organic acids of varying concentrations were tested. Among organic acids studied, treatment with 3% (w/v) oxalic acid was the most effective method and thus could be a safe substitution for SMS to prevent browning in banana blossoms.

Microbial contamination commonly occurs in microgreens due to contaminated seeds. This study investigated the decontamination effects of water wash (control), 5% hydrogen peroxide (H2O2), UV-C (36 watts), advanced oxidation process (AOP; H2O2 + UV-C), and improved AOP by combination with microbubbles (MBs; H2O2 + MBs and H2O2 + UV-C + MBs) on microbial loads, seeds’ viability, and physio-biochemical properties of microgreens from corresponding roselle seeds. Results showed that H2O2 and AOP, with and without MBs, significantly reduced total aerobic bacteria, coliforms, Escherichia coli (E. coli), and molds and yeast log count in seeds as compared to the control. Improved AOP treatment of H2O2 + UV-C + MBs significantly augmented antimicrobial activity against total bacteria and E. coli (not detected,) as compared to control and other treatments due to the formation of the highest hydroxy radicals (5.25 × 10−13 M). Additionally, H2O2 and combined treatments promoted seed germination, improved microbiological quality, total phenolic, flavonoids, and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) activity of the grown microgreens. Ascorbic acid content was induced only in microgreens developed from H2O2-treated seeds. Single UV-C treatment was ineffective to inactivate the detected microorganism population in seeds. These findings demonstrated that improved AOP treatment (H2O2 + UV-C + MBs) could potentially be used as a new disinfection technology for seed treatment in microgreens production.

ABSTRACT Nondestructive techniques based on visible and near‐infrared (Vis/NIR) spectroscopy were used for evaluation of the internal quality of fruit products. The objectives of the study were to investigate the feasibility of using Vis/NIR spectroscopic devices in transmission mode to predict the soluble solids content (SSC) and total acidity (TA) of fresh‐cut Kao Numpung pomelo. The determination of SSC and TA could be successfully performed through Vis/NIR spectroscopy using partial least squares regression. Preprocessing methods and interval partial least squares (iPLS) algorithms were analyzed. The results indicated that Vis/NIR spectrophotometry in combination with preprocessing techniques can be applied to predict the soluble solids and TA of fresh‐cut Kao Numpung pomelo. The optimal SSC model was established by standard normal variate transformation. The TA prediction model could be simplified by iPLS regression. PRACTICAL APPLICATIONS The research presents Vis/NIR spectroscopy that has been used for evaluation of the soluble solids and TA of fresh‐cut Kao Numpung pomelo. The results indicated that Vis/NIR spectroscopy devices combined with preprocessing techniques could be used to predict the internal quality of fresh‐cut Kao Numpung pomelo. Further, they can be used to develop an online system for the prediction of the internal quality of fresh‐cut pomelos.

This study determined the effects of salicylic acid (SA) and methyl jasmonate (MJ) on chilling injury (CI) of stored mangoes at low temperature. Mango fruits cv. Nam Dok Mai No.4 were dipped in SA and MJ at concentrations of 0.1 and 1 mM for 10 minutes and stored at 5±1 ºC with 90±2% RH for 42 days. Fruits were sampled every 7 days to determine the CI index, malondialdehyde (MDA) content, electrolyte leakage (EL), then transferred to room temperature (25±2 ºC, 70±2% RH) for ripening and analyzed for CI index, MDA content, EL, and ripening quality. The results show that mango fruits showed CI symptoms after 21 days of storage at 5 ºC and were unacceptable for consumption after 28 days of cold storage and after transfer to room temperature. SA and MJ treatments significantly reduced CI, MDA content, and EL in the mango skin and pulp during cold storage and after transfer to room temperature. Dipping fruits in 0.1 mM MJ, 1 mM MJ, and 0.1 mM SA reduced CI of cold storage and after transfer to room temperature up to 35 days, whereas dipping in 1 mM SA prolonged this up to 42 days without affecting fruit firmness, percentages of TA, and skin color (°Hue values) of the ripe fruits.

Blumea balsamifera (L.) DC., belonging to the Asteraceae family, also known as “ngai camphor,” is one of the traditional herbs used in Thailand for folk medicine and a component in local food and drinks. There was, however, no evidence indicating the presence of beneficial compounds at different leaf ages. Exploring various extraction solvents, we investigated the phenolics, flavonoids in particular quercetin content, antioxidant capacity, and antibacterial activity of immature and mature leaf extracts. The dried leaves were macerated in 50% ethanol, 95% ethanol, hexane, or decocted in water. Bioactive substances were analyzed by UV spectrophotometry and HPLC. Analysis of antioxidant capacity was done byDPPH, ABTS, FRAP, and NO scavenging assays. The antibacterial activity of immature leaf extract eluted with 50% ethanol was subsequentially evaluated in vitro. Extraction with 50% ethanol proved optimal, yielding 1.2–1.6-fold and 1.5-fold greater immature and mature leaf extracts than other solvents. More phenolics (1.2-fold), flavonoids (1.1-fold), quercetin content (4.8-fold), and antioxidant activity (1.3-fold) were found in the immature leaf extract. There was a significant positive correlation between antioxidant activity and bioactive compounds. The immature leaf extract eluted with 50% ethanol showed antibacterial activity against Staphylococcus aureus, with a minimum inhibitory concentration of 0.5 mg/mL. The immature leaves of B. balsamifera are a rich source of quercetin and phenolics, and 50% ethanol proved optimal for extracting bioactive components from these leaves.

Fresh-cut leafy vegetable has an image as a healthy, nutritious, and delicious product. However, the product still faces the challenge of quality retention and short shelf life, especially in tropical climate regions. Enzymatic browning in fresh-cut leafy vegetables is considered one of the most important attributes limiting the shelf life of the product. The hurdle approach using commercial vacuum precooling in combination with modified atmosphere packaging (MAP) as an alternative to the use of chemical preservatives to prevent enzymatic browning, an undesirable attribute that is easily detected by consumers, was investigated. The hurdle technology exhibited synergistic effects on fresh-cut lettuce, namely frillice iceberg, romaine, and red oak, in slowing down cut-surface browning, maintaining quality, delaying microbial growth, and extending shelf life of salad products at the retail level. The findings of the study verified the potential of the hurdle approach in delaying the effect of cutting as well as extending shelf life of the product stored at 4 ± 1 °C with 85% RH from three days to nine days with an additional unit cost of 1.05%. Therefore, our hurdle approach is anticipated as the practice with non-chemical and economical approach in the supply chain of the fresh-cut, leafy vegetables industry.

The effects of food additives (sodium carbonate, SC and potassium sorbate, PS) at 0%, 1%, 2%, 3% and 4% weight per volume on fungal spore germination of dragon fruit rot diseases, Colletotrichum gloeosporioides, C. capsici and Fusarium sp. were investigated on media. PS at all concentrations showed complete inhibition of spore germination in the three fungi. SC 2% inhibited the germination of C. gloeosporioides by 100% while SC 3% completely inhibited the germination of C. capsici and Fusarium sp. PS solution was selected to study its combined effects with hot water treatment on fruit rot disease and quality of dragon fruit artificially inoculated with C. gloeosporioides. The fruit samples were treated in a heated (55 °C) solution of 1% PS for 5 min and then cooled in tap water at 10 °C (PS-55 °C + cold H2O). Non-treated fruit and fruit treated with the fungicide carbendazim were used as controls. All samples were assessed after being kept at 13 °C for 15 d. The treatment of PS-55 °C + cold H2O reduced the severity of diseases and helped to delay chlorophyll degradation in the dragon fruit bracts, had little impact on the respiration rate, delayed ethylene production and maintained the total ascorbic acid content. However, PS-55 °C + cold H2O treatment, while having little initial effect, did reduce fruit firmness after 15 d of storage. The PS-55 °C + cold H2O treatment did not affect weight loss or the total soluble solids concentration. These findings showed that the PS-55 °C + cold H2O treatment could act as a safe alternative method for suppressing fruit rot disease while maintaining the quality of dragon fruit during cold storage.

Poor and inconsistent quality is a major barrier to increasing produce consumption, and the lack of shelf-life after purchase is the quality issue at retail displays of produce. This research aimed to investigate and identify cooling techniques, namely vacuum cooling and package icing used in supply chains, and any resulting extension of broccoli shelf-life, maintenance of physicochemical quality, and delay in microbial growth at retail stores. Broccoli (Brassica oleracea var. italica cv. Montop) sustainably grown in the highlands of northern Thailand, Chiang Mai Province, under the Royal Project Foundation was experimented on vacuum cooling and package icing were selected to precool broccoli to 4 ± 1 °C. The effects of vacuum cooling using a final pressure of 0.6 kPa for 30 min and package icing using liner Styrofoam boxes (the best ratio of broccoli to crushed ice was 1:1 w/w) on physicochemical qualities, microbial growth, and shelf-life in simulated refrigerated retail displays were examined. The results illustrated that the shelf-life and quality of broccoli could be extended using both vacuum cooling and package icing. Both precooling techniques inhibited the yellowing of florets, provided high sensory scores, delayed microbial growth, and could be able to extend the shelf-life of broccoli. However, package icing offered greater potential for maintaining quality, especially retaining bioactive compounds, and extending shelf-life, thereby increasing the produce market window from 5 to 12 days at 8 ± 1 °C with 85% RH. Therefore, package icing was recommended in the supply chain for fresh broccoli cv. Montop grown in northern Thailand.

Changes in color of dried chili in modified atmospheric packaging and storage temperature were investigated. Dried chili pods were packed in 100% CO2, 100% N2, vacuum, and normal air (control) before storage in cold (0 ± 2℃) and ambient (28 ± 2℃) conditions for 6 months. All samples at the ambient condition were increased in MC, pigment losses, and browning appearances. Non-enzymatic reaction markedly dominated on enhancing browning appearance as indicated by higher 5-hydroxymethylfurfural (HMF) and brown extractable compounds (BECs), as well as lower enzymatic activity of polyphenoloxidase (PPO) and peroxidase (POD). In contrast, these changes were delayed in cold condition. The 100% CO2 was able to prevent the change of color as indicated by higher L*, a*, chroma values, free-capsanthin, and total carotenoid contents. These suggest that 100% CO2 and cold conditions could be an alternative storage technique for dried chili to extend shelf storage. Novelty impact statement Delaying changes of color appearance and carotenoid contents in dried chili is optimized using effective and practical methods namely modified atmosphere packaging and cold condition. This finding provides an optimum solution to apply for producing dried chili during prolonged storage. This conducting trial could be a model to upscale for commercial usage.

Abstract: Postharvest diseases and loss of freshness are major problems that cause the deterioration of dragon fruit. The present study determined the effect of hot water treatment (HWT) at 50°C for 5 min followed by 1.0% chitosan and 0.2% κ-carrageenan-based composite coating to counter the issues. The results showed that HWT followed by the composite coating-enhanced antioxidant enzyme activities and reduced accumulation of H2O2 in the peel, which demonstrated the defensive response in the tissues leading to reduce disease development. The chitinase and β-1,3-glucanase did not show a significant effect in reducing the postharvest diseases of dragon fruit. While the HWT helped to increase phenolics content and antioxidant capacity in the pulp, the composite coating was crucial to maintain green color of the bract. Therefore, we concluded that HWT combined with composite coating controlled the diseases via antioxidant defensive response and maintained the overall quality of dragon fruit for 30 days of storage at 10°C.

We aimed to assess the effect of longkong peel extract (LPE)-silver particle-alginate coating on the postharvest decay and browning of longkong fruit during storage at 13°C and 90–95% relative humidity (RH). Longkong was coated with 0, 0.45 or 0.90 mg·L−1 LPE in silver particle-alginate solution and then stored at 13°C and 90–95% RH for nine days. In the mixture consisting of the longkong peel extract and silver solution, the silver particle size was modified to yield fine particles. Electron micrography showed the presence of silver particle sizes ranging in size from approximately 71–625 nm. Fruit coated without LPE exhibited severe browning, weight loss and decay incidence during storage. Coating with 0.45 and 0.90 mg·L−1 LPE significantly inhibited the increase in fruit browning by mainly reducing peroxidase (POD) and polyphenol oxidase (PPO) activities. LPE coating effectively reduced the longkong weight loss and decay incidence. No fruit treatment showed a significant titratable acidity change or increased soluble solids at the end of storage. These results indicate that coating with LPE is a promising approach to inhibit decay and browning and to maintain the quality of longkong during low-temperature storage.

ABSTRACT Light‐emitting diodes (LEDs) are commercially used as a light source to improve plant growth and antioxidants accumulation. Growth and antioxidant system in Chinese kale microgreens illuminated with blue, red and white LEDs and sunlight, as a control, with the same duration of illumination were investigated. The red LED with low light intensity significantly enhanced hypocotyl length and fresh weight of microgreens, while blue and white LEDs and sunlight showed fairly comparable effects. The synergistic effect of blue, green and red LEDs, as white LED was the most effective in enhancing the accumulation of secondary metabolites, namely, total glucosinolates, phenolic compounds and total ascorbic acid. Microgreens grown with blue and white LEDs showed higher DPPH (1,1‐diphenyl‐1‐picrylhydrazyl) radical scavenging activity and ferric reducing antioxidant power, whereas ABTS [2,2’‐Azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid)] radical cation (ABTS) fared better under sunlight and blue LEDs. Overall, microgreens treated with red LED significantly reduced H 2 O 2 and lipid peroxidation by only secondary metabolites. While blue and white LEDs treated samples utilised secondary metabolites, as well as, catalase and ascorbate peroxidase when compared to less effective superoxide dismutase in the control samples. The results suggest that light wavelength was a majority factor in enhancement antioxidant accumulation.