The Effect of Thermal Pretreatment and Packaging Conditions on the Shelf-life of Walnut Kernels

Authors

  • Farzad Goodarzi Agricultural Engineering Research Department, Hamedan Agricultural and Natural Resources Research and Education Center, AREEO, Shahrood, Iran
  • Hamed Fatemian 2Agricultural Engineering Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
  • Seyedhamidreza Ziaolhagh Agricultural Engineering Research Department, Agricultural and Natural Resources Research Center of Semnan Province (Shahrood), AREEO, Shahrood, Iran
Abstract:

This study aimed to extend the shelf life of walnut kernels by appropriate packaging conditions and physical methods. For this purpose, the kernels were heated at 50 or 70°C for 2 or 10 minutes. About 100g of walnuts were packed in low-density polyethylene (LDPE) packages under ordinary, vacuum or nitrogen conditions. Samples were stored for 18 months at room temperature. Peroxide value and acidy number were determined after 6, 12 and 18 months of storage. The results of the variance analysis showed that the effect of packaging conditions on peroxide value, and the effect of all factors on the acidity of the samples were significant (p < 0.01) for the 6- month storage. Walnuts packaged under nitrogen conditions had lower peroxide value than others, and the samples preheated at 70˚C had a lower acidity. After 12 months of storage, the effect of all factors on peroxide and the acidy number of walnuts were significant (p < 0.01). The lowest peroxide value and acidity were observed for walnuts preheated at 50˚C for two minutes. Finally, based on the obtained results, we recommend that walnut kernels should be preheated at 70˚C for two minutes and packaged under nitrogen or vacuum conditions. In this way, they could be stored for six months without perceived oxidation. The oxidation of walnuts would increase during storage for 12 to 18 months gradually, and their peroxide value and the acidity would exceed the desirable limits.

Upgrade to premium to download articles

Sign up to access the full text

Already have an account?login

similar resources

the effect of taftan pozzolan on the compressive strength of concrete in the environmental conditions of oman sea (chabahar port)

cement is an essential ingredient in the concrete buildings. for production of cement considerable amount of fossil fuel and electrical energy is consumed. on the other hand for generating one tone of portland cement, nearly one ton of carbon dioxide is released. it shows that 7 percent of the total released carbon dioxide in the world relates to the cement industry. considering ecological issu...

“the effect of risk aversion on the demand for life insurance: the case of iranian life insurance market”

abstract: about 60% of total premium of insurance industry is pertained?to life policies in the world; while the life insurance total premium in iran is less than 6% of total premium in insurance industry in 2008 (sigma, no 3/2009). among the reasons that discourage the life insurance industry is the problem of adverse selection. adverse selection theory describes a situation where the inf...

15 صفحه اول

Evaluation of Shelf Life of Walnut Kernels Treated by Antioxidants and Different Packaging under Two Temperatures

In this study, the effects of coatings made of chitosan (Chi) incorporating thyme essential oil (TEO) on lipid oxidation and changing color indexes of walnut kernels were investigated. Chi: pure, in accompany with TEO at concentrations of 500 and 1000 microliter per liter, in an aqueous coating solution, with different packaging methods: Gunny sack, polypropylene and active packaging, compared ...

full text

the washback effect of discretepoint vs. integrative tests on the retention of content in knowledge tests

در این پایان نامه تاثیر دو نوع تست جزیی نگر و کلی نگر بر به یادسپاری محتوا ارزیابی شده که نتایج نشان دهندهکارایی تستهای کلی نگر بیشتر از سایر آزمونها است

15 صفحه اول

the effect of task complexity on lexical complexity and grammatical accuracy of efl learners’ argumentative writing

بر اساس فرضیه شناخت رابینسون (2001 و 2003 و 2005) و مدل ظرفیت توجه محدود اسکهان (1998)، این تحقیق تاثیر پیچیدگی تکلیف را بر پیچیدگی واژگان و صحت گرامری نوشتار مباحثه ای 60 نفر از دانشجویان زبان انگلیسی بررسی کرد. میزان پیچیدگی تکلیف از طریق فاکتورهای پراکندگی-منابع تعیین شد. همه ی شرکت کنندگان به صورت نیمه تصادفی به یکی از سه گروه: (1) گروه موضوع، (2) گروه موضوع + اندیشه و (3) گروه موضوع + اندی...

15 صفحه اول

My Resources

Save resource for easier access later

Save to my library Already added to my library

{@ msg_add @}


Journal title

volume 11  issue 2

pages  159- 168

publication date 2020-06-30

By following a journal you will be notified via email when a new issue of this journal is published.

Hosted on Doprax cloud platform doprax.com

copyright © 2015-2023