Improving quality preservation of raw peanuts stored under different conditions during a long-term storage

Abstract

This research evaluated the chemical, microbiological, and sensory quality preservation of raw peanuts packed in high barrier ethylene vinyl alcohol bags (EVOH) under vacuum and in polypropylene (PP) bags, during 720 days of storage at 10° (T10) and 25 °C (T25). Peroxides (PV) and conjugated dienes (CD) remained almost stable in EVOH at 10 °C (EVOH-T10). The free fatty acid increase was greater in peanuts packaged in EVOH at 25 °C than at 10 °C. EVOH-T10 presented the lowest saturated/unsaturated and oleic/linoleic ratios, and the highest iodine values. The lowest γ-tocopherol decrease was for EVOH-T10. Peanuts stored in PP bags at 25 °C (PP-T25) showed the highest alkanes and the lowest decane,5,6-bis(2,2-dimethylpropylidene)-,(E,Z)- content at the end of storage. PP-T25 had the highest rate of roasted peanutty flavor decrease. Less than 10 CFU g−1 molds, yeasts, and aerobic mesophilic bacteria are detected for peanut samples, irrespective of packaging and storage temperature. Storage at 10 °C is associated with lesser quality deterioration than storage at 25 °C. All studied quality parameters are better preserved in raw peanuts packaged in EVOH except for free fatty acids. Practical Applications: Raw peanuts are used as primary ingredients which can be converted into value-added products like peanut butter, peanut flour, peanut oil, snacks, and other by-products. Nevertheless, preserving raw peanut quality has become a critical issue for peanut industry owing to peanut susceptibility to deterioration process. This research presents results about the chemical and sensory quality parameter changes of raw peanuts stored under different packaging materials and temperatures during a long-term storage to figure out which are better conditions to preserve raw peanuts as a high-quality product. Raw peanut quality preservation under a long-term storage period packed in high barrier plastic bags (EVOH) under vacuum and polypropylene bags (PP) stored at refrigeration temperatures (T10) and room temperature (T25).