Evaluation of some plant products against Trogoderma granarium everts and Rhyzopertha dominica fabricius in pearl millet and their effects on nutritional composition and organoleptic characteristics

Abstract

The present study was conducted to elucidate the nutritional and germination losses in 6–75 % infested grains of stored pearl millet caused by Trogoderma granarium Everts and Rhyzopertha dominica Fabricius. Four botanical powders (Neem, Lemon grass, Citrus and Eucalyptus) were used to manage these insect pests during storage and their subsequent impacts on nutritional and organoleptic characteristics as well as germination. Insect infestations manifested detrimental effects on nutritional quality and germination of grains in proportion to the increasing levels of infestations. Both insects caused significant reductions in the key nutritional parameters including crude protein, total soluble protein, total sugars, ash and crude fat contents with more pronounced losses caused by R. dominica, except crude fat content, where T. granarium infestation showed significantly higher negative impact. Conversely, the phenolic content of grains was higher with the increasing infestation levels of both insects. Principal component analysis (PCA) also revealed distinct differences between insect infested and insect-free grains. Among botanicals, Neem leaf powder at 2 % concentration effectively controlled the grain damage (69.88 %; 66.84 %) and weight loss (68.69 %; 55.85 %) by T. granarium and R. dominica, respectively for 6 months. However, Neem leaf powder at even 1 % concentration was more effective as compared to other botanical leaf powders (Eucalyptus, Citrus and Lemon grass). Treated pearl millet grains with Neem leaf powder showed minimum losses in nutritional parameters and germination. Khichdi (native palatable food recipe) prepared from uninfested but treated grains exhibited good acceptability.