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Subject: search.filters.subject.Enzymatic browning

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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
    ;
    Wongsuwan, Pratumtip
    ;
    Sripumimas, Sookmas
    ;
    Kang, Chuankai
    ;
    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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    Stress response of fresh-cut potatoes to laser irradiation before processing can prevent discoloration and maintain overall quality
    (2023-03-01)
    Wen, Bo
    ;
    Cui, Shijiang
    ;
    Suo, Xiaoyu
    ;
    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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    Substrate reactivity of polyphenol oxidase and browning inhibition of fresh-cut ‘nam dok mai si-thong’ mangoes by protein-based sericin coating
    (2020-01-01)
    Chimvaree, Chalida
    ;
    Cumsingnok, Thanakorn
    ;
    Wongs-Aree, Chalermchai
    ;
    Supapvanich, Suriyan
    ;
    Charoenrat, Theppanya
    Recent studies aimed to investigate five phenolic substrates’ reactivities in terms of PPO activity compared with browning symptom occurrence, as well as the efficiency of sericin extracted from ‘Nam Dok Mai Si-Thong’ mango in vitro on polyphenol oxidase (PPO) activity, and the efficiency of sericin coating on browning inhibition of fresh-cut ‘Nam Dok Mai Si-Thong’ mango during storage. The specificity of PPO activity was determined using various substrates such as caffeic acid, catechol, chlorogenic acid, 4-methylcatechol and pyrogallol. PPO extracted from ‘Nam Dok Mai Si-Thong’ mango was more actively specific to catechol and 4-methylcatechol than other substrates that revealed a darker browning color on mango pieces. In vitro, sericin inhibited the activity of PPO reacted with catechol and 4-methylcatechol substrate in mango extracts. The efficiency of sericin coating on browning inhibition of fresh-cut mangoes was then investigated. Application of a 2% sericin coating maintained the visual appearance including the L* value, browning index, browning score, and inhibited enzymatic browning incidence by lowering the increases in total phenol and PPO activity compared to the control during storage at 10°C for 4 days. However, sericin seemed to have no influence on phenylalanine ammonia-lyase (PAL) activity. Moreover, sericin coating enhanced the antioxidant activity of fresh-cut mango when compared to the control. In conclusion, we found that sericin coating is an effective option to maintain the visual appearance, and inhibit the enzymatic browning incidence, of fresh-cut ‘Nam Dok Mai Si-Thong’ mangoes during registered storage.
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    Effects of fresh Aloe vera gel coating on browning alleviation of fresh cut wax apple (Syzygium samarangenese) fruit cv. Taaptimjaan
    (2016-06-01)
    Supapvanich, S.
    ;
    Mitrsang, P.
    ;
    Srinorkham, P.
    ;
    Boonyaritthongchai, P.
    ;
    Wongs-Aree, C.
    The effect of natural coating by using fresh Aloe vera (A. vera) gel alleviating browning of fresh-cut wax apple fruits cv. Taaptimjaan was investigated. The fresh-cut fruits were dipped in fresh A. vera gel at various concentrations of 0, 25, 75 or 100 % (v/v) for 2 min at 4 ± 1 °C for 6 days. Lightness (L*), whiteness index (WI), browning index (BI), total color difference (ΔE*), sensorial quality attributes, total phenolic (TP) content, antioxidant activity and polyphenol oxidase (PPO) and peroxidase (POD) activities were determined. During storage, L* and WI of the fresh-cut fruits surface decreased whilst their BI and ΔE* increased. A. vera coating maintained the L* and WI and delayed the increase in BI and ΔE*, especially at 75 % A. vera dip. The fresh-cut fruits dipped in 75 % A. vera had the lowest browning score, the highest acceptance score and delayed the increase in TP content and PPO activity. However POD activity was induced by A. vera coating. Antioxidant activity had no effect on browning incidence of the fresh-cut fruits. Consequently, A. vera gel coating could maintain quality and retarded browning of fresh-cut wax apple fruits during storage.