Physiological and starch quality of potato tubers discarded from the potato chip industry in Mexico

Abstract

Agroindustrial potato (Solanum tuberosum L.) waste mainly includes peel and pulp; however, potatoes of low industrial quality are also discarded by industry. A viable alternative to give added value to these byproducts is the use of these as seeds, as well as the use of starch. The objective of this work was to evaluate the physiological quality (germination and vigor), starch content and relationship between these variables in discarded tubers from the industry through chemical-structural analyses to better understand their influence on starch composition. The physiological quality of the potatoes was evaluated through germination and vigor tests; likewise, starch was extracted, and the yield was determined. Physicochemical characterization of the starches was carried out through proximal and structural analysis using nuclear magnetic resonance (NMR). The results showed that the tubers had 100.00% germination and 98.66% vigor and were suitable for use as seeds. The starch yield did not significantly differ. However, characterization of the starch revealed significant differences (p ≤ 0.05) in moisture, ash, carbohydrate and amylose contents, which were influenced by the storage temperature (4 °C) of the tubers subjected to a vigor test, which interferes with enzymatic activity. During germination, the NMR results showed type B crystallinity, which is typical of tubers, indicating that the viability tests did not promote changes in the type of crystallinity. The results obtained can help us understand the effect of germination on the composition of starch and, accordingly, choose the most appropriate applications for this starch, whether food or nonfood.