Soaking of legumes results in the loss of macronutrients, micronutrients and phytochemicals. Fibre, protein and phytochemicals found in legumes exert emulsifying activity that may improve the structure and texture of gluten-free bread. The legume soaking water of haricot beans, garbanzo chickpeas, whole green lentils, split yellow peas and yellow soybeans were tested in this study for functional properties and use as food ingredients. Composition, physicochemical properties and effect on the quality of gluten-free bread were determined for each legume soaking water. Haricot beans and split yellow peas released the highest amount of solids in the legume soaking water: 1.89 and 2.38 g/100 g, respectively. Insoluble fibre was the main constituent of haricot beans legume soaking water, while water-soluble carbohydrates and protein were the major fraction of split yellow peas. High quantities of phenolics (∼400 µg/g) and saponins (∼3 mg/g) were found in the legume soaking water of haricot beans, whole green lentils and split yellow peas. High emulsifying activity (46 and 50%) was found for the legume soaking water of garbanzo chickpeas and split yellow peas, probably due to their protein content and high ratio of water-soluble carbohydrates to dry matter. Such activity resulted in softer texture of the gluten-free bread. A homogeneous structure of crumb pores was found for split yellow peas, opposing that of whole green lentils. A balance between the contents of yeast nutrients and antinutrients was the likely basis of the different appearances.
Summary
Drying pretreatments are usually considered as effective way to improve the quality of dried fruit products. The results of this research showed that the blanching (BL), ultrasonic (US) and freeze–thaw (FT) pretreatments could significantly shorten the drying time, and improve the rehydration capacity of the dried longan pulp. Compared with the control group (CK, without pretreatment), more irregular inner micropores were formed in the dried longan pulp treated with BL, US and FT. Besides, the brightness and yellowness of dried longan pulp with pretreatments were higher than those of the CK. The higher retention rates of total phenolic content (292.54 mg/100 g d.b.) and ascorbic acid (2.38 mg g−1 d.b.) were observed in the dried longan pulp treated with BL. Meanwhile, a higher chlorogenic acid content was found in the samples treated with FT (3.68 mg/100 g d.b.) and radio frequency (RF) (3.10 mg/100 g d.b.). Furthermore, the highest retention of a total free amino acid (1843.13 mg/100 g d.b) was exhibited by RF‐treated longan pulp. This work guides how pretreatments are applied prior to longan pulp drying.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.