Canned foods are a significant component of the diet of most people in both developed and developing countries, offering a wider choice of nutritious, good quality foods in a convenient form all-year-round. During canning, both desirable and undesirable changes occur in nutritional and sensory properties of foods, resulting from heat treatment employed for the destruction of microorganisms to achieve the desired commercial sterility. The extent of thermal processing, in terms of both temperature and duration of the treatment, is dependent upon the chemical and physical composition of the product, the canning medium and the conditions of storage, determining the product quality in terms of its sensory properties and nutrient content. This chapter reviews the major principles and operations used during food canning, identifies the nutritional and sensory changes occurring during the process and their effects on the quality of canned foods. In addition, it explains the use of response surface methodology (RSM) as modelling and optimization techniques used in the canning industry in recent times to manipulate canning processes to maintain the nutritional and sensory qualities of canned foods, using two recent studies where RSM was used to study the effect of pre-canning processes including blanching time, soaking time and sodium hexametaphosphate [(NaPO3)6] salt concentration on moisture, minerals, leached solids, phytates, tannins and hardness (texture) of cowpeas (Vigna unguiculata) and bambara groundnut (Voandzei subterranea). Regression models were developed to predict the pre-canning parameters that yield the best quality products, with minimal effects on the nutritional and textural properties of the products. The optimal conditions found to achieve the optimum quality of the canned cowpeas were blanching time of 5 min, soaking time of 12 h and [(NaPO3)6] salt concentration of 0.5%, and for the bambara groundnut; blanching time of 8 min, soaking time of 12 h and [(NaPO3)6] salt concentration of 0.5%. The combination of blanching, soaking and [(NaPO3)6] salt were modelled using RSM to retain the nutritional (mineral) content of products while reducing the anti-nutritional factors and the hardness of the canned products with acceptable quality characteristics, indicating that as recent advances in canning technology, modelling techniques could be used to control canning operations while retaining desirable product quality characteristics.
- Canning; thermal processing; nutritional quality; sensory quality; modelling;
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