تيمار پس از برداشت آب گرم به عنوان جايگزين غير شيميايي قارچ‌كش: تغييرهاي فيزيكوشيميايي و توانمندي سازگاري به تنش اكسايشي در ميوه ليموشيرين

Postharvest Hot Water Treatment as a Non-Chemical Alternative to Fungicide: Physicochemical Changes and Adaptability to Oxidative Stress in Sweet Lime Fruit

اﺛﺮ ﺗﯿﻤﺎرﻫﺎي ﭘﺲ از ﺑﺮداﺷﺖ ﻏﻮﻃﻪوري در آب ﮔﺮم و ﻗﺎرچﮐﺶ ﮐﺎرﺑﻨﺪازﯾﻢ ﺑﺮ وﯾﮋﮔﯽﻫﺎي ﺣﺴﯽ، ﻓﯿﺰﯾﮑﻮﺷﯿﻤﯿﺎﯾﯽ و ﭘﺎداﮐﺴﻨﺪه ﺗﻌﯿﯿﻦﮐﻨﻨﺪه ﮐﯿﻔﯿﺖ دروﻧﯽ و ﺑﺮوﻧﯽ ﻣﯿﻮه ﻟﯿﻤﻮﺷﯿﺮﯾﻦ ).Citrus limettioides Tan( ﻣﻄﺎﻟﻌﻪ ﺷﺪ. ﺗﯿﻤﺎرﻫﺎ ﺷﺎﻣﻞ 4 دﻗﯿﻘﻪ ﻏﻮﻃﻪوري در آب ﮔﺮم 45 درﺟﻪ ﺳﻠﺴﯿﻮس، 0/5 ﮔﺮم در ﻟﯿﺘﺮ ﻗﺎرچﮐﺶ ﮐﺎرﺑﻨﺪازﯾﻢ و آب ﻣﻘﻄﺮ )ﺷﺎﻫﺪ( ﺑﻮد. ﻣﯿﻮهﻫﺎ در دﻣﺎي 10 درﺟﻪ ﺳﻠﺴﯿﻮس و رﻃﻮﺑﺖ ﻧﺴﺒﯽ 85 درﺻﺪ ﺑﻪ ﻣﺪت 90 روز ﻧﮕﻬﺪاري و ارزﯾﺎﺑﯽﻫﺎ در ﻓﻮاﺻﻞ زﻣﺎﻧﯽ 30 روز اﻧﺠﺎم ﺷﺪ. در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﻣﯿﻮهﻫﺎي ﺷﺎﻫﺪ، ﻣﯿﻮهﻫﺎي ﺗﯿﻤﺎر ﺷﺪه ﺑﺎ آب ﮔﺮم ﮐﺎﻫﺶ وزن و ﭘﻮﺳﯿﺪﮔﯽ ﮐﻢﺗﺮ، ﺷﺎﺧﺺ ﻃﻌﻢ ﺑﻬﺘﺮ و ﻣﯿﺰان ﺑﯿﺶﺗﺮي ﻓﻨﻮل ﮐﻞ در ﭘﻮﺳﺖ و اﺳﮑﻮرﺑﯿﮏ اﺳﯿﺪ در آب ﻣﯿﻮه داﺷﺘﻨﺪ. ﭘﺲ از ﯾﮏ ﻣﺎه اﻧﺒﺎرﻣﺎﻧﯽ، آنﻫﺎ ﺳﻄﺢ ﻓﻌﺎﻟﯿﺖ ﭘﺎداﮐﺴﻨﺪه آﻧﺰﯾﻤﯽ ﺑﯿﺶﺗﺮ )ﺳﻮﭘﺮاﮐﺴﯿﺪ دﯾﺴﻤﻮﺗﺎز، ﮐﺎﺗﺎﻻز، آﺳﮑﻮرﺑﺎت ﭘﺮاﮐﺴﯿﺪاز و ﮔﺎﯾﺎﮐﻮل ﭘﺮاﮐﺴﯿﺪاز( و ﻣﺤﺘﻮاي ﭘﺎداﮐﺴﻨﺪهﻫﺎي ﻏﯿﺮآﻧﺰﯾﻤﯽ ﺑﯿﺶﺗﺮي ﻣﺎﻧﻨﺪ ﻓﻨﻮل ﮐﻞ در ﭘﻮﺳﺖ و اﺳﮑﻮرﺑﯿﮏ اﺳﯿﺪ در آب ﻣﯿﻮه در ﻗﯿﺎس ﺑﺎ ﺷﺎﻫﺪ دارا ﺑﻮدﻧﺪ. ﭘﺲ از آن، ﻓﻌﺎﻟﯿﺖ ﭘﺎداﮐﺴﻨﺪه آﻧﺰﯾﻤﯽ ﭘﻮﺳﺖ ﻣﯿﻮهﻫﺎي ﺗﯿﻤﺎر ﺷﺎﻫﺪ اﻓﺰاﯾﺶ ﯾﺎﻓﺖ در ﺣﺎﻟﯽ ﮐﻪ در ﻣﯿﻮهﻫﺎي ﺗﯿﻤﺎر ﺷﺪه ﺑﺎ آب ﮔﺮم ﮐﺎﻫﺶ ﻧﺸﺎن داد. ﺑﺮ ﻣﺒﻨﺎي ﻣﺤﺘﻮاي ﭘﺎداﮐﺴﻨﺪهﻫﺎي ﻏﯿﺮآﻧﺰﯾﻤﯽ و ارزﯾﺎﺑﯽ ﺣﺴﯽ ﭘﺲ از 3 ﻣﺎه اﻧﺒﺎرﻣﺎﻧﯽ، ﻣﯿﻮهﻫﺎي ﺗﯿﻤﺎر ﺷﺪه ﺑﺎ آب ﮔﺮم ﻣﻄﻠﻮبﺗﺮﯾﻦ ﮐﯿﻔﯿﺖ دروﻧﯽ و ﺑﺮوﻧﯽ را دارا ﺑﻮدﻧﺪ؛ در ﺣﺎﻟﯽ ﮐﻪ ﻣﯿﻮهﻫﺎي ﺗﯿﻤﺎرﺷﺪه ﺑﺎ ﻗﺎرچﮐﺶ ﺑﺎ ﻇﺎﻫﺮي رﻧﮓﭘﺮﯾﺪه، ﮐﻢﺗﺮﯾﻦ ﮐﯿﻔﯿﺖ رﻧﮓ ﭘﻮﺳﺖ و ﺳﻔﺘﯽ ﺑﺎﻓﺖ را داﺷﺘﻨﺪ. در اﯾﻦ زﻣﺎن، ﺑﺮرﺳﯽ ﻣﯿﺰان ﭘﺮاﮐﺴﯿﺪ ﻫﯿﺪروژن و ﻓﻌﺎﻟﯿﺖ ﭘﺎداﮐﺴﻨﺪه آﻧﺰﯾﻤﯽ ﭘﻮﺳﺖ ﻧﻤﺎﯾﺎنﮔﺮ ﺗﺤﻤﯿﻞ ﺷﺮاﯾﻂ ﺗﻨﺶ و آﺳﯿﺐ اﮐﺴﺎﯾﺸﯽ ﺑﯿﺶﺗﺮ ﺑﻪ ﻣﯿﻮهﻫﺎي ﺗﯿﻤﺎر ﻗﺎرچﮐﺶ ﻧﺴﺒﺖ ﺑﻪ ﺷﺎﻫﺪ ﺑﻮد. ﺑﻨﺎﺑﺮاﯾﻦ، ﺗﯿﻤﺎر ﻏﻮﻃﻪوري آب ﮔﺮم ﺑﻪﻋﻨﻮان روﺷﯽ اﯾﻤﻦ ﺟﻬﺖ ﺑﻬﺒﻮد و اﻓﺰاﯾﺶ ﻋﻤﺮ اﻧﺒﺎرﻣﺎﻧﯽ ﻟﯿﻤﻮﺷﯿﺮﯾﻦ و ﺟﺎﯾﮕﺰﯾﻨﯽ ﻣﻨﺎﺳﺐ ﺑﺮاي ﻗﺎرچﮐﺶ ﺷﯿﻤﯿﺎﯾﯽ ﺗﻮﺻﯿﻪ ﻣﯽﺷﻮد.

The effects of postharvest dip treatment in hot water and carbendazim fungicide on sensory, physicochemical, and antioxidant characteristics determining the internal and external quality of sweet lime (Citrus limettioides Tan.) fruit were studied. Treatments included a 4 min dip in 45 °C hot water, 0.5 g L-1 carbendazim solution and distilled water (control). Fruits were stored at 10 °C and 85% relative humidity for 90 days, with characteristics being measured at 30-day intervals. Compared to control fruits, treated fruits by hot water had lower weight loss and decay, better taste index, and higher content of total phenol in peel and ascorbic acid in the juice. After one month of the storage, they showed higher levels of enzymatic antioxidant activity (superoxide dismutase, catalase, ascorbate peroxidase, and guaiacol peroxidase) and more non-enzymatic antioxidants such as total phenol in peel and ascorbic acid in juice when compared to control. Afterwards, peel enzymatic antioxidant activity increased in control fruits while decreasing in hot water-treated fruits. Based on non-enzymatic antioxidants content and sensory evaluation after 3-months storage, hot water-treated fruits possessed the best internal and external quality, while fungicide-treated fruits with a pale appearance had the lowest quality in peel color and firmness. At this time, investigations on the peel content of hydrogen peroxide and enzymatic antioxidant activity revealed that fungicide-treated fruits experienced more stress and oxidative injury than control fruits. As a result, hot water dip treatment was recognized as a safe treatment for improving and extending the storability of sweet lime, as well as a suitable substitute for chemical fungicides.