Growth Region Impacts Cell Wall Properties and Hard-to-Cook Phenotype of Canned Navy Beans (Phaseolus vulgaris)

Jin Chu,Caroline Orfila,Peter Ho

doi:10.1007/s11947-020-02436-7

Abstract

Cellular mechanisms underpinning the hard-to-cook phenomenon are poorly understood. Navy beans (Phaseolus vulgaris) from the same cultivar but grown in different regions of North America showed different canning characteristics. Up to 46.4% more force was required to disrupt hard beans (HB) grown in Ontario compared with soft beans (SB) grown in Manitoba. HB absorbed 12.5% and 14.7% less water during blanching and canning, respectively. Microscopic assessment revealed that canning led to swelling of middle lamella and cell walls, but preservation of cell adhesion in both types of beans. Immunofluorescence microscopy showed reduced labelling of methyl-esterified homogalacturonan (HG) and more non-methyl-esterified HG and arabinan epitopes in HB. Compositional analysis indicated that the polysaccharides from HB were less water soluble and enriched in neutral sugars, including 46.5% more arabinose and 51.8% more galactose than in SB. ELISA analysis of polymers in the canning medium supported the increased solubility of cell wall polymers in SB. In the same cultivar, growth region affects cell wall properties with consequences for processing, eating and nutritional quality.

Highlights

Navy beans (Phaseolus vulgaris) canned in tomato sauce are a popular product consumed around the world
Hard-to-cook (HTC) defects manifest in a reduction of water absorption and solute exchange with the canning medium leading to hard beans and a thin sauce, attributes rejected by consumers
A batch of beans were grown in the Central Region of Manitoba characterised by short, highly humid and hot summers with long, extremely cold (− 40 °C) winters, while another batch were grown in the adjacent region of Ontario with humid continental climate characterised by longer warm (28 °C), humid summers and shorter milder winters (− 5 °C)

Summary

Introduction

Navy beans (Phaseolus vulgaris) canned in tomato sauce are a popular product consumed around the world. It is the most popular legume product in the UK as 50% of the UK population consumes around 300 g per week, higher than any other cooked vegetable source including peas and carrots (Henderson et al 2002). Canning quality is associated with high water absorption necessary for starch gelatinisation, softening and retention of bean structure. Hard-to-cook (HTC) defects manifest in a reduction of water absorption and solute exchange with the canning medium leading to hard beans and a thin sauce, attributes rejected by consumers. Several non-invasive processes have been designed to identify HTC beans from processing line, including visible and near-infrared spectroscopy (Mendoza et al 2014) and automated visual inspection (Erkinbaev et al 2017)

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