Economic evaluation of postharvest losses and utilization of hard‐to‐cook beans: A case study in Chile

Abstract

A methodology was developed to quantify postharvest economic losses due to bean hardening, and was used to predict losses in the main variety of beans consumed in Chile. Losses caused by bean hardening during storage in Chile were determined from a survey and a model of the post-production trade system. The survey involved nine farmers and four wholesalers in the bean growing area. After one year of storage, losses due to hardening were significant at both ends of the commercialization chain. The model used dynamic simulation of the post-harvest trade chain of beans in Chile to predict the losses. The overall economical loss due to this defect in tortola beans only, was estimated at almost US$4 million per annum. Of this loss, 34% was attributable to physical losses, 41% to nutritional losses and 24% to extra energy required to cook beans. Alternatives to reduce energy consumption were evaluated.

MODELING of BEAN HARDENING KINETICS DURING STORAGE

“…Dried beans are important staple foods in many less-developed countries. Severe physical and nutritional losses occur in these areas due to the hard-to-cook phenomenon, a textural defect resulting in a failure of cotyledons to soften during cooking Hohlberg et al 1991). In Central America alone, several million dollars are lost annually due to hardening of dry beans stored in large silos.…”

Hard Beans—A Problem for Growers, Processors, and Consumers

“…While this latter problem may not seem serious, for those of lower socioeconomic status in developing countries where bean consumption is high and most cooking energy is provided by wood fires, hard beans can be a very real hardship. For example, it has been estimated (Hohlberg et al, 1991) that, among the lower income strata of Chile, per capita bean consumption averages ≈ 5 kg per person per year, and the energy cost for food cooking represents as much as 11% of total income. Of additional concern, particularly with respect to child nutrition, is the documented (Hohlberg et al, 1991) reduction of protein efficiency as cooking time is lengthened.…”

“…For example, it has been estimated (Hohlberg et al, 1991) that, among the lower income strata of Chile, per capita bean consumption averages ≈ 5 kg per person per year, and the energy cost for food cooking represents as much as 11% of total income. Of additional concern, particularly with respect to child nutrition, is the documented (Hohlberg et al, 1991) reduction of protein efficiency as cooking time is lengthened. Typical data from Chile (Hohlberg et al, 1991) indicatethat, after 10 months storage in conditions where the mean maximum temperature ranged from 14 to 31C and the relative humidity (RH) ranged from 63% to 93%, beans approximately doubled in hardness and in cooking time, while the protein efficiency ratio decreased by ≈ 20% to considerably <1.0.…”

“…Of additional concern, particularly with respect to child nutrition, is the documented (Hohlberg et al, 1991) reduction of protein efficiency as cooking time is lengthened. Typical data from Chile (Hohlberg et al, 1991) indicatethat, after 10 months storage in conditions where the mean maximum temperature ranged from 14 to 31C and the relative humidity (RH) ranged from 63% to 93%, beans approximately doubled in hardness and in cooking time, while the protein efficiency ratio decreased by ≈ 20% to considerably <1.0. In Fig.…”

“…Earlier literature defined hard-to-cook (previously termed sclerema) beans as those that will not soften sufficiently because the soaked seeds do not become tender during a reasonable cooking time, while hard-shell refers to beans that fail to imbibe a sufficient quantity of water during the soaking step (Gloyer, 1921;Stanley and Aguilera, 1985). However, the distinction between these two storage-induced textural defects are Hohlberg et al (1991). Hardening data for commercially stored white Ontario beans (Bottom).…”