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    Preprocess Sonication Maintains Quality and Inhibits Browning of Fresh-cut Fruit Using Apples as the Fruit Model
    (2024-10-02)
    Thuamsuk, Pathitta
    ;
    Sinthusamran, Sirima
    ;
    Techavuthiporn, Chairat
    ;
    Supapvanich, Suriyan
    Ultrasonic (US) waves (sound waves) have been used to preserve and improve the quality of fresh fruits and vegetables. The goal of this study was to determine whether pre-process US treatment was useful in reducing browning and retaining certain aspects of fresh-cut ‘Gala’ apples’ quality. The apples were sonicated at a frequency of 120 kHz for 0, 5, 10 and 15 min before processing and then the processed apples were stored at 4±1°C. The US treatment at 5 min significantly delayed the loss of lightness, and increases in colour difference and browning index, and maintained whiteness compared to other treatments. The US treatment at 5 min controlled enzymatic browning reaction, probably due to inhibition of polyphenol oxidase activity. US treatments could delay the loss of hardness compared to the control treatment but had no influence on the total soluble solids content. Interestingly, US treatments induced antioxidant activity in fresh-cut apples during storage. In summary, the 5 min sonication could prevent browning and enhance the quality of fresh-cut apples during storage.
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    Short-term Anoxic Treatment of Litchi Fruit (Litchi chinensis Sonn. cv. Hong Huey) Delays Pericarp Browning and Maintains Physicochemical Quality During Storage
    (2023-01-01)
    Techavuthiporn, Chairat
    ;
    Jarerat, Amnat
    ;
    Nimitkeatkai, Hataitip
    The effect of short-term anoxic treatment prior to storage at ambient and cool temperatures on pericarp browning, fruit quality, secondary metabolites, antioxidant activity, and the browning enzyme of litchi (Litchi chinensis Sonn.) cv. Hong Huey were investigated. Litchi fruit were exposed to anoxic conditions for 6, 12, 18 and 24 h before storage at 28 ± 2°C for 5 days, or at 7 ± 2°C for 14 days. Anoxic treatment resulted in significantly decreases in electrical conductivity, weight loss, browning index, while maintaining the total soluble solids (TSS) and delaying increases in polyphenol oxidase (PPO) and peroxidase (POD) activities compared with control fruit. Furthermore, anoxic treatment increased litchi pericarp methanol extract antioxidant capacity, as measured by free-radical scavenging activity. This is associated with greater amounts of ascorbic acid, anthocyanins, and phenolic/flavonoid components as compared with control fruit. Additionally, anoxic treatment considerably delayed litchi fruit pericarp browning. This suggests that with adequate short-term anoxia duration, an enhanced non-enzymatic antioxidant process may directly or indirectly delay litchi pericarp browning. Thus, a short anoxic treatment enables harvested litchi quality to be sustained at ambient and cool temperatures. This non-chemical and inexpensive treatment deserves further development and application, especially in commercial distribution systems where cooling is insufficient.
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    Comparison of substrate reactivity of polyphenol oxidase and browning symptom of fresh cut 'Nam Dok Mai Si Thong' and 'Nam Dok Mai No. 4' mango in vitro and in vivo
    (2022-04-01)
    Chimvaree, C.
    ;
    Wongs-Aree, C.
    ;
    Supapvanich, S.
    ;
    Tepsorn, R.
    ;
    Boonyaritthongchai, P.
    'Nam Dok Mai Si Thong' and 'Nam Dok Mai No. 4' are popular cultivars for freshcut mango product in Thailand. Fresh-cut mango is considered as one of the most consumed products with the increasing market growth year by year. However, there are problems of fresh-cut mango due to surface browning and microbial contamination. This research was studied on the comparison of substrate reactivity of polyphenol oxidase and browning symptom of fresh-cut mango cultivars 'Nam Dok Mai Si Thong' and 'Nam Dok Mai No. 4'. Enzymatic browning of both 'Nam Dok Mai' mango revealed that polyphenol oxidase activity (PPO) in 'Nam Dok Mai Si Thong' was higher than 'Nam Dok Mai No. 4' mango. Five phenolic substrates of PPO including caffeic acid, catechol, chlorogenic acid, 4-methyl catechol and pyrogallol was individually dropped onto 'Nam Dok Mai Si Thong' and 'Nam Dok Mai No. 4' mango pulp surface for testing the specific substrates of 'Nam Dok Mai' mango's PPO (in vivo). 'Nam Dok Mai No. 4' mango cubes underwent darker browning symptom when treated with chlorogenic acid, 4-methyl catechol and caffeic acid, respectively, while 'Nam Dok Mai Si Thong' mango cubes showed a darker color when treated with 4-methyl catechol, catechol and pyrogallol. In vitro, the specificity of PPO activity of mango extract was determined using various substrates as caffeic acid, catechol, chlorogenic acid, 4-methylcatechol and pyrogallol. PPO extracted from 'Nam Dok Mai Si Thong' and 'Nam Dok Mai No.4' mango was more actively specific to catechol and 4-methylcatechol than other substrates which revealed the higher activity of PPO.
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    Thermal processes improving antibrowning potential of mixed Aloe vera and pineapple core extract solution on browning inhibition of fresh-cut apples
    (2022-01-01)
    Takeungwongtrakul, Sirima
    ;
    Sai-Ut, Samart
    ;
    Waraput, Thidarat
    ;
    Supapvanich, Suriyan
    Aloe vera and pineapple fruit extract have been applied as natural antibrowning agent for fresh-cut products. The effect of different thermal treatment processes (high-temperature–short-time pasteurisation at 80 ± 1 °C for 15 s and sterilisation at 121 ± 1 °C for 20 min) of mixed A. vera and pineapple core extract solution at a ratio of 1:1 (v/v) (AP) on enzymatic browning control of fresh-cut ‘Gala’ apples was investigated. Both thermal processes increased the antioxidant activities of AP solution compared to unheated AP solution. Coating of both thermal processed AP solutions alleviated the increased browning incidence of the fresh-cut apples during storage. Compared to sterilised AP coating, the pasteurised AP coating maintained visual appearance, whiteness index (WI) and L* values as well as inhibited browning incidence due to the prevention of increased a*, b*, ΔE* and browning index (BI) values of fresh-cut apples during storage. The fresh-cut apples coated with pasteurised AP had lower total phenolic compounds and polyphenol oxidase activity compared to the samples coated with sterilised AP. These suggested that the suitable thermal process was helpful to enhance antibrowning ability of AP coating agents to control enzymatic browning reaction of fresh-cut fruits.
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