Our understanding and prevention of postharvest losses are critical if we are to feed a growing global population. Insect infestation-related losses of stored commodities are typically considered only in terms of quantitative, physical weight loss. Insect infestation affects the nutritional value and some nutritional components are impacted more severely than others. We infested maize and cowpea grain with commonly occurring stored product insect pests, and mapped infestation levels against nutritional composition over a 4-to-6 month storage period to analyse how insect infestation relates to different macro- and micro-nutrient contents. Insect infestation decreased the carbohydrate content of the stored grains, causing a relative increase in the proportion of protein and fibre in the remaining grain, and moisture content also increased. Sitophilus zeamais preferentially fed in the floury endosperm of maize, resulting in more carbohydrate loss relative to protein loss. Conversely, Prostephanus truncatus consumed the germ and endosperm, disproportionately reducing the fat, protein, iron and zinc grain contents. Nutrients are distributed more homogenously within cowpea than in maize grains, but Callosobruchus maculatus infestation increased the relative protein, fat, iron and zinc to carbohydrate ratios. This indicates how the nutrient content of insect-infested stored grain depends upon the grain type, the infesting insect, and the infestation level. Insect infestation therefore has consequences for human nutrition beyond those of grain weight loss. Using data collected on the changing nutritional composition of grain over time, with and without insect infestation, we modelled the associations between infestation and nutritional quality to predict estimated nutritional losses that could be associated with consumption of insect-infested stored maize and cowpea.

中文翻译：

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测量储存玉米和豇豆虫害的营养成本

如果我们要养活不断增长的全球人口，我们对收获后损失的理解和预防至关重要。储存商品的虫害相关损失通常仅从数量、物理重量损失方面考虑。虫害影响营养价值，某些营养成分比其他营养成分受到的影响更严重。我们用常见的储藏产品害虫侵染玉米和豇豆，并在 4 到 6 个月的储存期内根据营养成分绘制侵染水平，以分析昆虫侵染与不同宏观和微量营养素含量的关系。虫害降低了储存谷物的碳水化合物含量，导致剩余谷物中蛋白质和纤维的比例相对增加，水分含量也增加。Sitophilus zeamais 优先喂食玉米的粉状胚乳，导致相对于蛋白质损失更多的碳水化合物损失。相反，Prostephanus truncatus 消耗了胚芽和胚乳，不成比例地减少了脂肪、蛋白质、铁和锌的谷物含量。营养物质在豇豆中的分布比在玉米粒中更均匀，但 Callosobruchus maculatus 感染增加了相对蛋白质、脂肪、铁和锌与碳水化合物的比例。这表明受虫害的储藏谷物的营养成分如何取决于谷物类型、虫害和虫害水平。因此，虫害对人类营养的影响超出了谷物减重的影响。使用收集到的有关谷物营养成分随时间变化的数据，有无虫害，