振动胁迫对双孢菇褐变与抗氧化能力的影响

    Effects of vibration stress on the browning and antioxidant capacity of Agaricus bisporus

    • 摘要: 为了研究运输过程中振动胁迫对双孢菇贮藏品质的影响,探究振动胁迫处理后双孢菇褐变和抗氧化能力的关系,为开发减振包装提供理论依据。该研究以品种W192双孢菇为试材,在3.33 Hz频率下进行不同时长(0、8、16、24 h)的模拟运输振动处理,在4 ℃贮藏15 d并测定相关指标。结果表明,振动胁迫加剧了双孢菇菌盖褐变程度,振动处理组亮度L*值始终小于对照组(P<0.05),贮藏15 d,振动处理24 h组的褐变指数(Browning Index, BI)和色差值(ΔE)分别是对照组的1.53倍和1.57倍。振动处理加大了细胞膜渗透率,加速了非酶抗氧化物质如酚类物质、维生素C和谷胱甘肽(Glutathione, GSH)的消耗;同时促进抗氧化酶抗坏血酸过氧化物酶(Ascorbate peroxidase, APX)、过氧化物酶(Peroxidase, POD)和超氧化物歧化酶(Superoxidase dismutase, SOD)的酶活峰值提前出现,对照组的酶活变化幅度较之振动处理组则更加平缓,贮藏后期活性更高。对照组过氧化氢酶(Catalase, CAT)和谷胱甘肽还原酶(Glutathione Reductase, GR)酶活始终高于振动处理组(P<0.05),且振动胁迫时间越长,酶活下降的速度越快。这种变化也体现在1,1-二苯基-2-三硝基苯肼(1,1-Diphenyl-2-picrylhydrazyl, DPPH)自由基的清除率的变化,贮藏15 d后,振动处理24 h组的DPPH自由基清除率显著低于对照组(P<0.05)。通过相关性分析发现双孢菇贮藏期褐变与抗氧化能力密切相关,振动处理后双孢菇抗氧化能力越强则其褐变程度越低。振动胁迫对双孢菇的损伤是累积的,运输振动时间越长其损伤越大,应当尽可能缩短双孢菇物流运输时间,采取合理的保鲜技术维持其抗氧化能力,并通过缓冲包装降低菇体之间的相对摩擦从而减少振动损伤。研究结果为开发双孢菇物流减震包装技术提供参考。

       

      Abstract: Agaricus bisporus is one of the most popular foods rich in nutrition and with unique flavor among the edible fungus. However, the edible part of A. bisporus is prone to water loss and mechanical damage during the process of postharvest transportation, thereby leading to browning and decay, due to its high water content without the protective tissue in the outer skin. This study aims to explore the effect of vibration stress on the storage quality of A. bisporus during logistics and transportation for better cushioning packaging, and then to determine the relationship between browning degree and antioxidant capacity of A. bisporus after vibration stress treatment. W192 strain of A. bisporus was treated in a simulated transportation vibration with different duration times (0, 8, 16, and 24 h) at the frequency of 3.33 Hz, and then stored at 4℃ for 15 days. The results showed that the browning degree of A. bisporus cap was aggravated under vibration stress, where the brightness (L*) in the vibration treatment group was generally lower than that in the control group (P < 0.05) during the storage. After 15d of storage, the browning index (BI) and total chromatism (ΔE) of samples treated by the vibration for 24 h were 1.53 and 1.57 times higher than that in the control, respectively. Vibration treatment increased the permeability of cell membrane, thereby accelerating the consumption of non-enzymatic antioxidants, such as phenols, vitamin C, and glutathione (GSH), particularly for better activities of ascorbate peroxidase (APX), peroxidase (POD), and superoxide dismutase (SOD). Compared with the vibration treatment, the activities of APX, POD, and SOD changed more slowly in the control group, indicating that the higher activities had remained during the later stage of storage. The activities of catalase (CAT) and glutathione reductase (GR) were usually higher in the control group than those in the vibration treatment (P < 0.05) during storage, indicating that the enzyme activities decreased fast, as the duration of vibration stress increased. After 15d of storage, the 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging rate of samples treated by vibration for 24 h was also significantly lower than that in the control (P < 0.05). Correlation analysis showed that there was a great significance between the antioxidant capacity and browning index of A. bisporus under vibration stress. More importantly, the antioxidant capacity of A. bisporus was proportional to the browning degree after vibration treatment. As such, a relatively lower browning was achieved under the stronger antioxidant capacity of A. bisporus after vibration treatment. Therefore, it can be inferred that the damage of A. bisporus caused by vibration stress was a cumulative process, where the mechanical damage was greater for the longer transportation vibration. Correspondingly, shorter transportation and reasonable preservation were recommended for the higher antioxidant capacity of A. bisporus. Particularly, the reduction of relative friction between mushroom bodies and cushioning packaging can be expected to minimize the vibration damage during transportation. The finding can also provide a sound reference for the development of logistics and transportation packaging in most vegetables.

       

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