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Effects of packaging and pre-storage treatments on aflatoxin production in peanut storage under controlled conditions

Darko, Clara, Kumar Mallikarjunan, Parameswaran, Kaya-Celiker, Hande, Frimpong, EmmanuelAnokye, Dizisi, Komla
Journal of food science and technology 2018 v.55 no.4 pp. 1366-1375
Aspergillus flavus, aflatoxins, bags, blanching, microbial growth, oxygen, packaging, peanuts, peroxide value, polypropylenes, roasting, temperature, water activity
This study reports on aflatoxin production and peanut (Bailey’s variety) quality, for four peanut pre-storage treatments; [(Raw clean (Raw-Cl), Raw inoculated with Aspergillus flavus NRRL 3357 (Raw-Inf), inoculated partially roasted but not-blanched (PRN-blanch); and inoculated partially roasted, blanched with discolored nuts sorted out (PR-blanched)]. All four treated samples were packaged in four different packaging systems [polypropylene woven sacks (PS), hermetic packs (HP), hermetic packs with oxygen absorbers (HPO), and vacuumed hermetic packs (HPV)] and stored under controlled conditions at a temperature of 30 ± 1 °C and water activity of 0.85 ± 0.02, for 14 weeks. Raw-Inf samples in PS had a higher fungal growth with a mean value of 8.01 × 10⁴ CFU/g, compared to the mean values of samples in hermetic packs: 1.07 × 10³ CFU/g for HP, 14.55 CFU/g for HPO, and 57.82 CFU/g for HPV. Similarly, the hermetic bags were able to reduce aflatoxin level of the Raw-Inf samples by 50.6% (HP), 63.0% (HPV), and 66.8% (HPO). Partial roasting and blanching in PS also reduced aflatoxin level by about 74.6%. Quality maintenance was the best for peanuts in HPO, recording peroxide value (PV) of 10.16 meq/kg and p-Anisidine (p-Av) of 3.95 meq/kg compared to samples in polypropylene woven sacks which had PV of 19.25 meq/kg and p-Av of 6.48 meq/kg. These results indicate that using zero-oxygen hermetic packaging, instead of the conventional polypropylene woven sacks, helped to suppress aflatoxin production and quality deterioration. Also, partially roasted, blanched and sorted peanuts showed a potential for reducing aflatoxin presence during storage.