استفاده از پوشش‌های خوراکی متیل‌سلولز و موم کارنوبا و بسته‌بندی با اتمسفر اصلاح شده در بهبود کیفیت سیب قرمز لبنانی

ﻣﻘﺪﻣﻪ: ﺳﯿﺐ از ﻣﯿﻮه ﻫﺎﯾﯽ اﺳﺖ ﮐﻪ ﻧﮕﻬﺪاری آن در ﺳﺮدﺧﺎﻧﻪ ﺑﺴﯿﺎر ﻣﺘﺪاول ﻣﯽ ﺑﺎﺷﺪ و از ﻣﻬﻢ ﺗﺮﯾﻦ ﻋﻮارض ﻣﻌﻤﻮل در دوره ﻧﮕﻬﺪاری ﺳﯿﺐ در ﺳﺮدﺧﺎﻧﻪ ﻣﯽ ﺗﻮان ﺑﻪ از دﺳﺖ دادن آب و ﭘﮋﻣﺮدﮔﯽ، ﮐﺎﻫﺶ وزن و ﺳﻔﺘﯽ ﺑﺎﻓﺖ، ﺗﻐﯿﯿﺮات در ﻣﺰه و ﺑﻮ و ﻗﻬﻮه ای ﺷﺪن اﺷﺎره ﮐﺮد. اﺳﺘﻔﺎده از ﭘﻮﺷﺶ ﻫﺎی ﺧﻮراﮐﯽ ﺑﺮ روی ﻣﯿﻮه ﻫﺎ و ﺳﺒﺰی ﻫﺎ ﻣﻮﺟﺐ ﮐﺎﻫﺶ اﻓﺖ رﻃﻮﺑﺖ، ﺳﺮﻋﺖ ﺗﻨﻔﺲ وﺗﺮﮐﯿﺒﺎت ﻣﻐﺬی ﺷﺪه و ﺑﻪ ﻃﻮر ﮐﻠﯽ ﺑﺎﻋﺚ اﻓﺰاﯾﺶ ﻣﺎﻧﺪﮔﺎری و ﺣﻔﻆ ﮐﯿﻔﯿﺖ ﻣﺤﺼﻮﻻت ﺗﺎزه ﻣﯽ ﺷﻮد. ﻫﺪف از اﯾﻦ ﻣﻄﺎﻟﻌﻪ اﺳﺘﻔﺎده از دو ﻧﻮع ﭘﻮﺷﺶ ﺧﻮراﮐﯽ ﻣﺘﯿﻞ ﺳﻠﻮﻟﺰ و ﻣﻮم ﮐﺎرﻧﻮﺑﺎ ﺑﻪ ﻣﻨﻈﻮر ﮐﺎﻫﺶ ﺷﺪت ﺗﻨﻔﺲ ﺑﻪ ﻫﻤﺮاه ﺑﺴﺘﻪ ﺑﻨﺪی ﺑﺎ اﺗﻤﺴﻔﺮ اﺻﻼح ﺷﺪه ﺑﺮای اﻓﺰاﯾﺶ ﻣﺎﻧﺪﮔﺎری و ﺣﻔﻆ ﮐﯿﻔﯿﺖ ﺳﯿﺐ درﺧﺘﯽ ﺑﻮد. ﻣﻮاد و روش ﻫﺎ: در ﭘﮋوﻫﺶ ﺣﺎﺿﺮ ﺳﯿﺐ ﺗﺎزه ﺑﺎ دو ﻧﻮع ﭘﻮﺷﺶ ﺧﻮراﮐﯽ ﻣﺘﯿﻞ ﺳﻠﻮﻟﺰ و ﻣﻮم ﮐﺎرﻧﻮﺑﺎ ﭘﻮﺷﺶ دﻫﯽ ﺷﺪه و ﺳﭙﺲ در ﺑﺴﺘﻪ ﻫﺎﯾﯽ از ﺟﻨﺲ ﻓﯿﻠﻢ ﭘﻼﺳﺘﯿﮑﯽ ﺳﻪ ﻻﯾﻪ pe/pa/pe ، ﺗﺤﺖ درﺻﺪ ﻣﺸﺨﺺ ﮔﺎز 1- ﻫﻮای ﻣﻌﻤﻮﻟﯽ در ﺑﺴﺘﻪ ﻣﻨﻔﺬدار ﻧﻤﻮﻧﻪ ﺷﺎﻫﺪ ، 2- %6 اﮐﺴﯿﮋن+ 4% دی اﮐﺴﯿﺪ ﮐﺮﺑﻦ+90% ﻧﯿﺘﺮوژن و 3- ﻫﻮای ﻣﻌﻤﻮﻟﯽ در ﺑﺴﺘﻪ ﻧﻔﻮذ ﻧﺎﭘﺬﯾﺮ، اﺗﻤﺴﻔﺮ اﺻﻼح ﺷﺪه ﻏﯿﺮﻓﻌﺎل ﺑﺴﺘﻪ ﺑﻨﺪی ﮔﺮدﯾﺪ. ﻧﻤﻮﻧﻪ ﻫﺎ در دﻣﺎی c˚2 و رﻃﻮﺑﺖ ﻧﺴﺒﯽ 85% ﺑﺮای ﻣﺪت ﺳﻪ ﻣﺎه ﻧﮕﻬﺪاری ﺷﺪﻧﺪ. آزﻣﻮن ﻫﺎی ﺗﻐﯿﯿﺮات وزن، ﺳﻔﺘﯽ ﺑﺎﻓﺖ، ﺗﻐﯿﯿﺮات رﻧﮓ، ﻣﻮاد ﺟﺎﻣﺪ ﻣﺤﻠﻮل و ﺗﻐﯿﯿﺮات درﺻﺪ ﮔﺎز اﮐﺴﯿﮋن و ﮐﺮﺑﻦ دی اﮐﺴﯿﺪ ﺑﺴﺘﻪ ﺑﻨﺪی در زﻣﺎن ﯾﮏ، دو و ﺳﻪ ﻣﺎه ﭘﺲ از ﺷﺮوع اﻧﺒﺎرﻣﺎﻧﯽ اﻧﺠﺎم ﮔﺮﻓﺖ. ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﭘﻮﺷﺶ ﺧﻮراﮐﯽ ﻣﺘﯿﻞ ﺳﻠﻮﻟﺰ اﺛﺮ ﻣﺜﺒﺖ و ﻣﻌﻨﯽ داری ﺑﺮ ﮐﺎﻫﺶ وزن و ﺗﻐﯿﯿﺮات رﻧﮓ در ﺳﯿﺐ ﻫﺎ داﺷﺘﻪ و ﺳﻔﺘﯽ ﺑﺎﻓﺖ در ﻧﻤﻮﻧﻪ ﻫﺎی ﭘﻮﺷﺶ دار ﺑﯿﺸﺘﺮ از ﻧﻤﻮﻧﻪ ﺷﺎﻫﺪ ﺑﻮد p≤0/05 . در ﭘﺎﯾﺎن زﻣﺎن ﻧﮕﻬﺪاری ﻧﻤﻮﻧﻪ ﻫﺎ ﺑﯿﺸﺘﺮﯾﻦ ﺳﻔﺘﯽ 958/2 ﻣﺮﺑﻮط ﺑﻪ ﻧﻤﻮﻧﻪ ﺑﺎ ﭘﻮﺷﺶ ﻣﺘﯿﻞ ﺳﻠﻮﻟﺰ و ﮐﻤﺘﺮﯾﻦ ﺳﻔﺘﯽ 780/2 ﻣﺮﺑﻮط ﺑﻪ ﻧﻤﻮﻧﻪ ﺑﺪون ﭘﻮﺷﺶ ﺷﺎﻫﺪ ﺑﻮد ﭘﻮﺷﺶ ﺑﻪ ﻋﻨﻮان ﯾﮏ ﻣﺎﻧﻊ ﺑﺮای ﺗﺒﺎدل ﮔﺎز ﺑﯿﻦ ﻣﯿﻮه و ﻣﺤﯿﻂ ﻋﻤﻞ ﮐﺮد. در ﻧﻤﻮﻧﻪ ﻫﺎی ﭘﻮﺷﺶ دﻫﯽ ﺷﺪه ﺑﺎ ﻣﺘﯿﻞ ﺳﻠﻮﻟﺰ اﻓﺖ وزن ﻧﻤﻮﻧﻪ ﻫﺎ ﺑﻪ ﻃﻮر ﻣﻌﻨﯽ داری ﮐﻤﺘﺮ از ﺳﺎﯾﺮ ﻧﻤﻮﻧﻪ ﻫﺎ ﺑﻮده و اﻓﺖ وزن ﺑﺎ ﺳﺮﻋﺖ آﻫﺴﺘﻪ ﺗﺮی ﺻﻮرت ﮔﺮﻓﺖ p≤0/05 . در ﭘﺎﯾﺎن ﻣﺎه ﺳﻮم ﺑﯿﺸﺘﺮﯾﻦ 7/6 وﮐﻤﺘﺮﯾﻦ 4/7 ﻣﯿﺰان اﻓﺖ وزن ﺑﻪ ﺗﺮﺗﯿﺐ ﻣﺮﺑﻮط ﺑﻪ ﻧﻤﻮﻧﻪ ﺑﺪون ﭘﻮﺷﺶ و ﻧﻤﻮﻧﻪ ﺑﺎ ﭘﻮﺷﺶ ﻣﺘﯿﻞ ﺳﻠﻮﻟﺰ ﺑﻮد. در ﭘﺎﯾﺎن زﻣﺎن ﻧﮕﻬﺪاری ﻧﻤﻮﻧﻪ ﻫﺎ ﺑﻪ ﺗﺮﺗﯿﺐ ﻧﻤﻮﻧﻪ ﺑﺪون ﭘﻮﺷﺶ ﺷﺎﻫﺪ دارای ﺑﯿﺸﺘﺮﯾﻦ ﺑﺮﯾﮑﺲ 17/2 و ﻧﻤﻮﻧﻪ ﺑﺎ ﭘﻮﺷﺶ ﻣﻮم ﮐﺎرﻧﻮﺑﺎ 16/1 دارای ﮐﻤﺘﺮﯾﻦ ﻣﯿﺰان ﺑﺮﯾﮑﺲ ﺑﻮد. در ﺗﻤﺎﻣﯽ ﻧﻤﻮﻧﻪ ﻫﺎ ﻣﯿﺰان *l در ﭘﺎﯾﺎن زﻣﺎن اﻧﺒﺎرﻣﺎﻧﯽ ﮐﺎﻫﺶ ﯾﺎﻓﺖ. در ﺗﻤﺎم ﻃﻮل ﻣﺪت اﻧﺒﺎرﻣﺎﻧﯽ ﺳﯿﺐ ﻫﺎ، ﻣﯿﺰان *l ﻧﻤﻮﻧﻪ ﻫﺎی ﭘﻮﺷﺶ دار ﺑﯿﺸﺘﺮ از ﻧﻤﻮﻧﻪ ﻫﺎی ﺷﺎﻫﺪ ﺑﻮد. ﻣﯿﺰان *l در ﻧﻤﻮﻧﻪ ﻫﺎی ﺷﺎﻫﺪ ﮐﺎﻫﺶ ﭘﯿﺪا ﮐﺮد و ﺑﻪ 19/2 رﺳﯿﺪ، در ﺣﺎﻟﯿﮑﻪ در ﻧﻤﻮﻧﻪ ﻫﺎی دارای ﭘﻮﺷﺶ ﻣﺘﯿﻞ ﺳﻠﻮﻟﺰ ﺑﻪ 25/6 رﺳﯿﺪ. ﻧﺘﯿﺠﻪ ﮔﯿﺮی: ﻣﺘﯿﻞ ﺳﻠﻮﻟﺰ ﭘﻮﺷﺶ ﻣﻨﺎﺳﺒﯽ ﺑﺮای ﺣﻔﻆ ﮐﯿﻔﯿﺖ و اﻓﺰاﯾﺶ زﻣﺎن ﻣﺎﻧﺪﮔﺎری ﺳﯿﺐ درﺧﺘﯽ وارﯾﺘﻪ رددﻟﯿﺸﺰ ﺑﻮد. اﯾﻦ ﭘﻮﺷﺶ ﺑﺎﻋﺚ ﺟﻠﻮﮔﯿﺮی از اﻓﺖ وزن، ﺣﻔﻆ ﺳﻔﺘﯽ ﺑﺎﻓﺖ، ﮐﺎﻫﺶ ﺗﻐﯿﯿﺮات رﻧﮓ ﻧﻤﻮﻧﻪ ﻫﺎ ﻧﺴﺒﺖ ﺑﻪ ﻧﻤﻮﻧﻪ ﻫﺎی ﺷﺎﻫﺪ ﺷﺪ.

effect of methylcellulose and carnauba wax coating with modified atmosphere packaging on the improvement quality of red delicious apple

introduction:  the quality of fresh fruits and vegetables, and thus their shelf life, is reduced due to changes such as moisture loss, enzymatic browning, tissue decay, and microbial growth. the use of an edible coating on fruits and vegetables during storage will increase shelf life by controlling the moisture migration, respiration rate, and oxidation. as apple is one of the most important raw materials for many foods and is grown in many countries around the world, it is important to keep apples fresh. the use of methylcellulose and carnauba wax coating with modified atmosphere packaging for maintaining the quality and prolonging the shelf life of red delicious apples.materials and methods: in this study, fresh apples red delicious were coated by two types of coating materials methyl cellulose and carnauba wax then samples packed in three layers bags pe/pa/pe with normal air condition control , active modified atmosphere and inactive passive modified atmosphere, samples stored at 2°c for 3 month. thereafter, their quality characteristics such as weight losses, color changes, hardness and change in packaging gas percentage, were tested and evaluated.   results: data showed coated samples had better properties as compared to the uncoated samples. the property was more obvious in samples coated by methylcellulose. in coating samples, weight losses were significantly p≤0.05 less than uncoated samples, and also weight loss was slower.  at the end of the storage time, the highest firmness 958.2 was related to the sample with methyl cellulose coating and the lowest firmness 780.2 was related to the sample without coating control . in the methyl cellulose coated samples, the weight loss of the samples was significantly lower than the other samples and the weight loss occurred at a slower rate p≤0.05 . at the end of the third month, the highest 7.6 and the lowest 4.7 weight loss was related to the sample without coating and the sample with methylcellulose coating, respectively. at the end of the sample storage time, the uncoated sample control had the highest brix 17.2 and the sample coated with carnauba wax 16.1 had the lowest brix. in all samples, the amount of l* decreased at the end of the storage time. during the entire storage period of apples, the amount of l* of the coated samples was higher than that of the control samples. the amount of l* in the control samples decreased and reached 19.2 , while it reached 25.6 in the samples with methyl cellulose coating.  conclusion:  the results of the present study showed that methylcellulose was an appropriate coating to maintain the quality and increase the shelf-life of apples red delicious .