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Preharvest blue diode laser irradiation enhances betalain biosynthesis, antioxidant responses, and postharvest quality of red amaranth microgreens during storage
(2026-12-01)
Supapvanich, Suriyan
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Sripumimas, Sookmas
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Li, Man
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Kang, Chuankai
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Puisoongnoen, Nichaphat
In recent years, light-based technologies have attracted growing interest as a postharvest strategy for maintaining the quality of leafy vegetables and microgreens. This study investigated the effects of blue diode laser irradiation (450 nm, 3 h) on the postharvest quality, antioxidant system, and betalain biosynthesis of red amaranth (Amaranthus tricolor) microgreens during storage at 4 ± 1 °C for 9 d. Blue laser treatment effectively maintained visual quality and reduced weight loss compared with untreated samples. Treated microgreens exhibited significantly lower accumulation of hydrogen peroxide (H₂O₂), superoxide anion (O₂⁻), and lipoxygenase (LOX) activity during storage, indicating reduced oxidative stress and membrane lipid peroxidation. In addition, laser-treated samples maintained higher antioxidant capacity, including ferric reducing antioxidant power (FRAP) and DPPH radical scavenging activity, together with greater retention of total phenolics, flavonoids, vitamin C, and glutathione. Activities of antioxidant-related enzymes, including phenylalanine ammonia-lyase (PAL), superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), were also significantly enhanced by laser irradiation. Furthermore, blue laser treatment effectively delayed chlorophyll degradation and increased betacyanin accumulation during storage. Gene expression analysis revealed significant upregulation of betalain biosynthesis-related genes, including AtrWRKY42–2, AtrCYP76AD1, AtrMYB72, AtrDODA1–1, and AtrB5-GT, particularly during the early storage period. Principal component analysis clearly separated laser-treated and control samples, confirming the positive association between laser irradiation, antioxidant defense, pigment retention, and overall quality maintenance. These findings demonstrate that short-term blue laser irradiation is a promising postharvest technology for enhancing antioxidant defense, regulating betalain biosynthesis, and extending the shelf life of red amaranth microgreens.
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Laser light as a novel postharvest strategy to suppress chlorophyll degradation and oxidative stress in pakchoi (Brassica rapa subsp. Chinensis)
(2026-01-01)
Wen, Bo
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Kang, Chuankai
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Yang, Ting
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Zhan, Qi
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Chen, Tingyuan
Short-term diode laser light irradiation is an emerging physical treatment for preserving quality and enhancing oxidative stress resilience in postharvest commodities. Rapid deterioration, including leaf yellowing, is a major factor limiting the postharvest shelf life of pakchoi. This study investigated the effects of short-term exposure to blue (450 nm) and red (660 nm) diode laser light on quality maintenance, oxidative stress mitigation, and chlorophyll metabolism in pakchoi stored at 20 °C for 5 days. The results demonstrated that 660 nm red laser irradiation significantly maintained visual quality and green coloration while reducing weight loss more effectively than 450 nm blue laser light and the untreated control. Both laser treatments reduced respiration rates and ethylene production and induced partial stomatal closure. Additionally, both treatments regulated oxidative stress responses by lowering malondialdehyde (MDA) content, lipoxygenase (LOX) activity, and reactive oxygen species (ROS) accumulation (H₂O₂ and O₂⁻), while enhancing both enzymatic and non-enzymatic antioxidant systems. The red and blue laser treatments also preserved total chlorophyll content by suppressing the expression of chlorophyll degradation genes (BcPAO, BcNYC1, BcPPH1) and upregulating chlorophyll biosynthesis genes (BcCAO, BcCHLH). Among the treatments, the 660 nm red laser exhibited the strongest effects, as confirmed by higher maximum quantum efficiency of PSII photochemistry (Fv/Fm) values and principal component analysis (PCA). Overall, these findings demonstrate that 660 nm laser irradiation synergistically modulates chlorophyll metabolism and antioxidant defense, offering an effective and practical physical strategy to extend the postharvest shelf life of leafy vegetables.
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Pre-peeling salicylic acid and post-slicing melatonin treatment: Effects on browning inhibition and quality improvement in lotus root slices
(2025-12-01)
Supapvanich, Suriyan
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Wongsuwan, Pratumtip
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Sripumimas, Sookmas
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Kang, Chuankai
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Yang, Ting
Browning is a major problem in lotus root slices. This study examined the combined effects of pre-peeling salicylic acid (SA) and post-slicing melatonin (MT) on browning inhibition and quality retention. Preliminary tests identified optimal conditions as 3 mM SA for 30 min and 0.1 mM MT for 5 min. Intact roots were treated with SA, slices with MT, or both, and stored at 4 °C for 12 days. The combined SA + MT more effectively maintained visual quality by suppressing polyphenol oxidase and peroxidase activities, preserving firmness via reduced polygalacturonase, β-galactosidase, and cellulase activities, and enhancing antioxidant capacity, total phenolics, and flavonoids. It also lowered H<inf>2</inf>O<inf>2</inf> content and lipoxygenase activity, mitigating oxidative stress. Post-slicing MT alone achieved similar browning control but was less effective in texture preservation. These findings indicate that integrated SA and MT application is a promising strategy to extend shelf life and maintain physicochemical quality of fresh-cut lotus root.
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Protecting celtuce (Lactuca sativa L. var. augustana) slices against storage-induced oxidative stress and discoloration by using diode laser exposure
(2024-12-01)
Wen, Bo
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Xiao, Yinghui
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Zhang, Weiyan
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Cui, Shijiang
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Li, Junbing
Diode laser irradiation is a novel approach applied to preserve the quality of fresh commodities and minimise oxidative processes, including browning in fresh-cut products. The objective of this study was to investigate the efficacy of diode laser treatment in enhancing the quality of celtuce slices during refrigerated storage at 4 °C. The celtuce slices were subjected to a 660 or 450 nm diode laser for 5 min and then stored for 10 d. Both laser treatments hindered the progression of weight loss and firmness increase in the celtuce slices. The use of a 450 nm diode laser effectively prevented the development of browning and preserved the surface colour by inhibiting the increase in a* and overall colour difference values, as compared to other treatments, during storage for 10 d. The diode laser treatment suppressed the increase in oxidative stress by lowering the levels of MDA, H<inf>2</inf>O<inf>2</inf>, and O-<inf>2</inf> while retaining a high level of DPPH scavenging activity, AsA, and antioxdant enzyme activities, including SOD, CAT, APX, and GR, in comparison to the untreated slices. The treatment enhanced chlorophylls content due to the up-regulation of LsHEMA1 gene and down-regulation of LsNYC1 gene. The treatment also inhibited factors involving enzymatic browning reaction by suppressing PAL activity, total phenols content, PPO activity and LsPPO gene expression. These suggest that the blue diode laser exposure at 450 nm for 5 min is an effective approach hindering oxidative stress and discoloration of celtuce slices during storage.
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Efficacy of blue-diode laser exposure on the postharvest quality maintenance of strawberries
(2024-12-01)
Cui, Shijiang
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Supapvanich, Suriyan
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Xiao, Yinghui
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Zhang, Weiyan
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Li, Junbing
The purpose of this research was to evaluate the impact of postharvest laser irradiation on strawberry visual quality and texture. In preliminary studies, strawberries were exposed to diode laser radiation for 2.5 or 5 min at wavelengths of 405, 450 and 660 nm. The treatment at 450 nm for 2.5 or 5 min kept the visual appearance without deterioration after storage at 20 °C, 70% RH, for 4 d. The diode laser at 450 nm was selected to screen the exposure duration, and 2 min of exposure preserved a desirable visual appearance without decay during storage at 20 °C, 70% RH, for 6 d. Subsequently, the impacts of a diode laser at 450 nm for 2 min on the quality and softening of strawberries during storage at 4 °C for 14 d were observed. The laser treatment delayed strawberry softness and visual fungal development and maintained total acidity level, but had no effect on the total soluble solids content and BrimA value during storage. The membrane degradation of the laser-treated fruits was retarded, due to the inhibitions of the increases in malondialdehyde levels, phospholipase-D (PLD) activity and FaPLD gene expression. The activities of cell wall hydrolases such as polygalacturonase (PG) and β-galactosidase (β-Gal) activity and the expressions of FaPG1 and Faβ-Gal1genes were suppressed by the laser treatment. The laser treatment had no effect on the cellulase activity. These findings show that diode laser irradiation is a promising postharvest approach for efficiently preventing strawberry softness and deterioration.
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Stress response of fresh-cut potatoes to laser irradiation before processing can prevent discoloration and maintain overall quality
(2023-03-01)
Wen, Bo
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Cui, Shijiang
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Suo, Xiaoyu
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Supapvanich, Suriyan
Browning is accepted as a main factor affecting quality of fresh cut products. Physical treatments maintaining quality of fresh-cut products have been recently considered by consumer safer than chemical treatments. This study investigated whether preprocess diode laser irradiation can improve the physicochemical quality of fresh-cut potatoes. Laser irradiation at a 450-nm wavelength for 30 min prevented the browning of potato slices during short-term storage at 25 °C. Compared with no treatment, preprocess laser irradiation preserved the appearance and whiteness and inhibited browning and delayed weight loss in potato slices when refrigerated at 4 °C for 96 h. The increases in the total phenol concentration and phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD) activities of fresh-cut potatoes were diminished after laser irradiation. Moreover, the laser irradiation also enhanced antioxidant activities in the samples. The expression of PAL, PPO and POD genes was suppressed by the laser treatment. Therefore, the laser irradiation at 450 nm wavelength for 30 min effectively eliminates discolouration and improves quality of sliced potatoes during cold storage.
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Efficiency of Ultrasonic Incorporated Glutathione Treatment in Preserving the Physicochemical Quality and Preventing the Browning of Lotus Rhizome Slices
(2021-12-01)
Wen, Bo
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Li, Da
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Du, Xianfeng
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Kedbanglai, Phacharee
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Tang, De
This study investigated the efficacy of 40-kHz (200 W) ultrasonication (US) for 2 min combined with glutathione (GSH) at 0.5% w/v (US + GSH) in preventing browning and preserving the physicochemical quality of lotus rhizome slices stored in a 4 ± 1 °C refrigerator. According to the visual appearance of the slices, US + GSH treatment more effectively inhibited the browning of the cut surface than did GSH or US treatment alone. US + GSH and GSH treatments were more effective than US and control treatments in preserving the slices’ colour attributes, such as their lightness and whiteness index values, and potentially retarded enzymatic browning reactions and increases in browning index and total colour difference values. Moreover, the application of US and US + GSH treatments noticeably preserved the texture of the slices. None of the treatments affected the total sugar content during storage. The US + GSH treatment markedly enhanced the ferric reducing antioxidant potential of the slices during storage. The slices treated with US, GSH, and US + GSH exhibited slower reductions in 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity than did the controls. In conclusion, US + GSH treatment is a feasible approach for inhibiting browning, maintaining texture, and inducing antioxidant activity in lotus rhizome slices during storage.
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Effects of simultaneous ultrasonic and cysteine treatment on antibrowning and physicochemical quality of fresh-cut lotus roots during cold storage
(2020-10-01)
Wen, Bo
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Li, Da
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Tang, De
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Huang, Zhen
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Kedbanglai, Phacharee
The effects of ultrasound (US) power of 200 w at a constant frequency of 40 kHz for 2 min, 0.01 % cysteine (Cys) and combinative application of US and Cys (US + Cys) on browning prevention and quality of lotus root slices were compared during storage at 4 °C for 12 d. The visual appearance, colour attributes including L*, b*, hue, chroma, whiteness index (WI), browning index (BI) and colour difference (ΔE*), browning enzymes activities such as polyphenol oxidase (PPO) and peroxidase (POD), total phenols concentration, texture, total sugars concentration and antioxidant activities were evaluated. US + Cys retarded browning incidence being greater than Cys, US and control treatments, respectively. The browning retardation was concomitant with the retention of high L* and WI values and low b*, chroma, BI and ΔE* value. Cys and US + Cys controlled the increased PPO activity rather than US. All treatments delayed the increased total phenols concentration compared to control. All treatments maintained hardness of lotus root slices, especially US, and did not affect total sugars concentration. Both sonication treatment enhanced ferric reducing antioxidant potential (FRAP) whilst free radical scavenging activity was enhanced by Cys. In conclusion, both of the Cys and US could prevent browning and maintain physicochemical quality of lotus root slices and the simultaneous US and Cys treatment exhibited synergistic antibrowning effect.
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Ultraviolet-C treatment maintains physicochemical quality of water bamboo (Zizania latifolia) shoots during postharvest storage
(2019-06-01)
Wen, Bo
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Cheng, Zechao
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Hu, Yanmei
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Boon-Ek, Yaowapa
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Wongs-Aree, Chalermchai
Ultraviolet-C (UV-C) treatment has been used as a method to maintain postharvest quality for many kinds of fruits and vegetables. In this study, we investigated the effects of UV-C treatment on physicochemical changes in water bamboo shoots (WBS) during storage. WBS were treated with UV-C at the doses of 0 (control), 1.06, 2.12, 3.18, 4.24, 5.30, and 6.36 kJ m −2 at 20 °C ± 2 °C for 2 d. The increase in greenness of WBS was inhibited by all UV-C treatments, but the 4.24 kJ m −2 UV-C treatment maintained lightness and whiteness index values of WBS better than other treatments. Thus, the 4.24 kJ m −2 UV-C treatment was selected for use to determine the physicochemical quality of WBS during refrigeration at 10 °C. The UV-C treatment retarded the increases in greenness, chlorophyll a, chlorophyll b, and total chlorophyll content, resulting in maintenance of the whiteness index and colour attributes. It also prevented toughness by retarding lignin increase during storage. Moreover, it induced antioxidant activities and bioactive compounds, especially total phenol, and maintained the activities of antioxidant enzymes such as phenylalanine ammonia lyase and catalase during storage. However, the UV-C treatment did not affect ascorbic acid content and the activities of ascorbic acid peroxidase and guaiacol-peroxidase. These results indicated that UV-C treatment at the dose of 4.24 kJ m -2 is a potential alternative for maintaining physicochemical quality and improving the nutritional quality of WBS during storage.
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Effect of honey and calcium dips on quality of fresh-cut nectarine (Prunus persica L. Batsch)
(2018-04-01)
Wen, Bo
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Wu, Xiaozhen
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Boon-Ek, Yaowapa
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Xu, Lan
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Pan, Haifa
The effects of calcium chloride (CaCl<inf>2</inf>) and honey dips were investigated on the quality of fresh-cut nectarines. Nectarine fruit samples at the commercially ripe stage were wedged and then dipped in distilled water, 50% honey, 1% CaCl<inf>2</inf> or 1% CaCl<inf>2</inf> combined with 50% honey solutions, followed by storage at 4 ± 0.5 °C and 90 ± 2% relative humidity for 7 d. The following parameters were investigated during storage: firmness, total soluble solids (TSS), superficial color, color darkening score and index, total phenols content and the enzyme activities of peroxidase and polyphenol oxidase (PPO). CaCl<inf>2</inf> and CaCl<inf>2</inf> + honey solution dips improved the texture and maintained the TSS content. Honey and CaCl<inf>2</inf> + honey suppressed an increase in the color difference. Minor changes were found in color attributes (lightness (L*), hue and chroma values), color darkening, total phenols content and PPO activity during storage. CaCl<inf>2</inf> + honey maintained the quality of the nectarines by delaying color change and firmness loss.

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