Quantitative assessment of molecular, microstructural, and macroscopic changes of red kidney beans (Phaseolus vulgaris L.) during cooking provides detailed insights in their cooking behavior

Nguyen T H An; Patricia Namutebi; Ann Van Loey; Marc E Hendrickx

doi:10.1016/j.foodres.2024.114098

Quantitative assessment of molecular, microstructural, and macroscopic changes of red kidney beans (Phaseolus vulgaris L.) during cooking provides detailed insights in their cooking behavior

Food Res Int. 2024 Apr:181:114098. doi: 10.1016/j.foodres.2024.114098. Epub 2024 Feb 3.

Authors

Nguyen T H An¹, Patricia Namutebi², Ann Van Loey³, Marc E Hendrickx⁴

Affiliations

¹ KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Laboratory of Food Technology, Kasteelpark Arenberg 22, Box 2457, 3001 Leuven, Belgium. Electronic address: thihoaian.nguyen@kuleuven.be.
² KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Laboratory of Food Technology, Kasteelpark Arenberg 22, Box 2457, 3001 Leuven, Belgium.
³ KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Laboratory of Food Technology, Kasteelpark Arenberg 22, Box 2457, 3001 Leuven, Belgium. Electronic address: ann.vanloey@kuleuven.be.
⁴ KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Laboratory of Food Technology, Kasteelpark Arenberg 22, Box 2457, 3001 Leuven, Belgium. Electronic address: marceg.hendrickx@kuleuven.be.

PMID: 38448107
DOI: 10.1016/j.foodres.2024.114098

Abstract

Quantitative changes at different length scales (molecular, microscopic, and macroscopic levels) during cooking were evaluated to better understand the cooking behavior of common beans. The microstructural evolution of presoaked fresh and aged red kidney beans during cooking at 95 °C was quantified using light microscopy coupled with image analysis. These data were related to macroscopic properties, being hardness and volume changes representing texture and swelling of the beans during cooking. Microstructural properties included the cell area (A_cell), the fraction of intercellular spaces (%A_is), and the fraction of starch area within the cells (%A_s/c), reflecting respectively cell expansion, cell separation, and starch swelling. A strong linear correlation between hardness and %A_is (r = -0.886, p = 0.07), along with a significant relative change in %A_is (∼5 times), suggests that softening is predominantly due to cell separation rather than cell expansion. Regarding volume changes, substantial cell expansion (A_cell increased by ∼1.5 times) during the initial 30 min of cooking was greatly associated with the increase in the cotyledon volume, while the significance of cell separation became more prominent during the later stages of cooking. Furthermore, we found that the seed coat, rather than the cotyledon, played a major role in the swelling of whole beans, which became less pronounced after aging. The macroscopic properties did not correlate with %A_s/c. However, the evolution of %A_s/c conveyed information on the swelling of the starch granules during cooking. During the initial phase, the starch granule swelling mainly filled the cells, while during the later phase, the further swelling was confined by the cell wall. This study provides strong microscopic evidence supporting the direct involvement of the cell wall/ middle lamella network in microstructural changes during cooking as affected by aging, which is in line with the results of molecular changes.

Keywords: Aging; Microstructure; Quantitative microscopy; Swelling; Texture.

MeSH terms

Cooking
Phaseolus*
Starch
Vegetables

Substances

Starch