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Subject: Processing and Food Engineering × Author: Gurjeet Kaur × Start date: 2018 × Type: Thesis × Thesis Type: Ph.D ×
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    Development of process protocol for packaging and storage of groundnut kernels
    (Punjab Agricultural University, Ludhiana, 2022) Gurjeet Kaur; Sidhu, Gagandeep Kaur
    The spring grown groundnuts are prone to quality deterioration owing to high temperature and relative humidity during the harvesting. The present work investigated the impact of treatments and packaging systems on quality of groundnut kernels during storage. Spring varieties J87 and TG37A developed by Punjab Agricultural University were selected for the study. The fresh groundnut pods were dried using solar hybrid dryer at 60°C till the moisture content below 10% was achieved. Sample was decorticated and clean and healthy kernels were selected for the study. The sorption isotherms were developed at 25, 35 and 45°C temperature and water activity (aw) range of 0.110-0.975 in order to predict the suitable storage conditions. The equilibrium moisture content increased with increase in aw and the isotherms of type II were observed. The experimental data was fitted to seven mathematical models and Guggenheim Anderson de Boer and Double Log Polynomial were considered to be best fitted models. The safe storage conditions determined from best fitted models indicated that moisture content of J87 and TG37A varieties should not exceed 7.70 and 9.86 % (db) respectively during storage. The samples were subjected to three treatments viz. dry roasting (166 °C for 7 min), ozonation treatment (6 mg/L for 30 min) and combined ozonation-roasting (ozonation at 6 mg/L for 30 min followed by dry roasting at 166 °C for 7 min). The groundnut kernels were packed in low-density polyethylene (L), aluminum lined LDPE Ziplock bags (S) and aluminum laminate bags under nitrogen flushing (N) and in high barrier 5-layer polymeric laminate (PE/adhesive/EVOH/adhesive/PE) under vacuum packaging techniques. The samples were kept under ambient conditions for 12 months of storage period. Samples were analyzed for different quality parameters viz., moisture content, color characteristics, fracturability, radical scavenging activity, flavonoid content, protein, free fatty acids and aflatoxin content. Results indicated that treatments led to significantly (p<0.05) affect all the quality parameters except the hue angle and free fatty acids of J87 kernels and hue angle and chroma of TG37A kernels. The aflatoxin content after treatments exhibited values that were below the FDA established limit (20 µg/kg) for aflatoxins in groundnut kernels. The moisture content, chroma, total color difference, free fatty acids were found to be increased and hue angle, fracturability and protein content decreased with increase in storage period. FFA of groundnut kernels packaged in different materials were within acceptable limits (< 3%) for ozonated and ozonated-roasted samples. Radical scavenging activity and flavonoid content indicated a declined trend and then inclined as storage period approached 12 months. The maximum variation in quality parameters were observed in LDPE and zip lock bags. Vacuum and nitrogen flushed bags provided stable conditions with minimum alterations in quality of kernels. Microbial evaluation indicated dominance of Fusarium, Penicillium and Aspergillus spp. which was maximum in zip pouches followed by LDPE bags. It can be concluded that dried groundnut kernels with combined ozonation-roasting treatment, vacuum packaged in 5-layer modified polymeric laminate can be stored at ambient storage conditions for 12 months with maximum retention of quality parameters.