Physico-Chemical, Microstructural, and Cooking Characteristics of Faba Bean (Vicia faba) Varieties From New Zealand

Abstract

This research examines the physical and microstructural properties of New Zealand faba beans (Vicia faba), with a focus on their influence on swelling, hydration, and cooking characteristics. Four native varieties (Early Long Pod, Evergreen, Coles Dwarf, and Janet) were studied. No statistically significant differences were found in the seed physical characteristics, including sphericity, equivalent diameter, thousand kernel weight, seed volume, and surface area, among the varieties. The faba bean seeds showed high levels of protein (24%–27%) and starch content (35%–39%), with Coles Dwarf exhibiting a significantly higher protein content. Cooking times varied among the varieties and were decreased by at least 30 min for all varieties when seeds were soaked before cooking. Evergreen seeds took the least time to cook, while those from Janet required the longest time, which was significantly higher than the other varieties, especially when soaked faba beans were used for cooking. These results were in accordance with the scanning electron microscopy (SEM) results, which revealed significant differences in cotyledon cell wall thickness and surface ridge morphology. Despite a relatively high hydration capacity, Janet required the longest cooking time, suggesting that its thicker cotyledon cell walls and folded surface topography may limit thermal softening despite adequate water uptake. The rapid visco analyzer (RVA) results also showed that the Janet flour exhibited significantly higher peak viscosity, indicating strong water-holding and gelation potential during heating. The Coles Dwarf variety, which exhibited the highest protein content, displayed pronounced surface ridges but showed a significantly lower hydration index, highlighting how macronutrient composition and microstructure jointly influence water uptake and pasting behavior. These results highlight the varying suitability of each variety for different food applications, considering their distinct physico-chemical and cooking properties.