نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانش آموخته کارشناسی ارشد

2 دانشیار گروه علوم و صنایع غذایی دانشکده کشاورزی دانشگاه تربیت مدرس

چکیده

نگهداری مواد غذایی همواره ذهن بشر را به خود مشغول کرده است به طوری که طی سالیان دراز روش­های متعدد را به منظور حفظ نیازمندی­های خود به کار گرفته یا ابداع کرده است که می­توان به استفاده از انبار سرد، پوشش­های پلاستیکی و اتمسفر اصلاح شده اشاره کرد.  در این پژوهش، اثر بسته­بندی کاهوی پیچ معمول (رقم Romain)،در اتمسفر اصلاح شده با میزان اکسیژن بالا:  G1(40درصد اکسیژن + 15درصد دی­اکسید کربن +45 درصد نیتروژن)؛ G2 (70 درصد اکسیژن + 15 درصد دی­اکسید کربن+ 15 درصد نیتروژن)؛ و G3 (100 درصد اکسیژن) در پوشش پلی­اتیلنی با دو ضخامت 50 و 40 میکرومتر (به ترتیب P1 و P2) در دمای 4 درجه ‌سلسیوس و به مدت 16 روز آزمایش، و خصوصیات فیزیکوشیمیایی و بیولوژی آن بررسی شد.  کمترین میزان آلودگی از نظر بار میکروبی کل و نیز از نظر کپک و مخمر در نمونه با ترکیب گازی G3 و پوشش پلی­اتیلنی با ضخامت 50 میکرومتر دیده شد.  همین نمونه از نظر pH و رنگ نیز در بهترین وضعیت قرار داشت.  بیشترین درصد کاهش وزن مربوط به ترکیب گازی G3 و پوشش پلی‌اتیلنی با ضخامت 40 میکرومتر به دست آمد.  در همین ترکیب گازی و ضخامت پوشش، درصد مادة جامد انحلال‌پذیر بیشترین کاهش را نشان داد.  در نتیجه­گیری کلی می­توان گفت ترکیب گازی G3 و پوشش P1 مؤثر­ترین تیمارها در نگهداری کاهو بودند و در این شرایط می­توان کاهو را تا دو هفته به خوبی نگهداری کرد.

عنوان مقاله [English]

Optimal Packaging Conditions to Prolong Shelf Life of Lettuce (Lactuca sativa L.) in a Modified Atmosphere

چکیده [English]

Food preservation has always been a concern for mankind. Different methods have been developed to preserve food for long periods, such as cold storage, plastic covers, and modified atmosphereThis study examined the physicochemical and biological effects of a modified atmosphere on packaged Romaine lettuce at three levels (G1: 40% oxygen, 15% carbon dioxide, 45% nitrogen; G2: 70% oxygen, 15% carbon dioxide, 15% nitrogen; G3: 100% oxygen). The lettuce was packaged in 40 µm (P1) or 50 µm (P2) thick polyethylene at 4°C and stored for 16 days. The least polluted sample was G3 using P2, as assessed by the total number of microorganisms, mold and yeast. This sample was also in the best condition, as measured by pH and color. The highest percentage of weight loss was for G3 and P1; it also showed the greatest decrease in the percentage of soluble solid materials. The results showed that G3 and P1 was the best combination to preserve packaged Romaine lettuce. This combination was effective for two weeks of preservation.

کلیدواژه‌ها [English]

  • Modified Atmosphere
  • Packaging
  • Polyethylene Cover
  • Preservation Time
  • Romaine Lettuce
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