Processing of Sugar-Coated Red Kidney Beans (Phaseolus vulgaris): Fate of Oligosaccharides and Phytohemagglutinin (PHA), and Evaluation of Sensory Quality

• Published in: Journal of food science 2006-11, Vol.71 (9), p.C521-C526
• Main Authors: Siddiq, M, Nyombaire, G, Dolan, K.D, Matella, N.J, Harte, J.B
• Format: Article
• Language: English
• Subjects: antinutritional factors; Beans; Biological and medical sciences; coatings; color; consumer acceptance; flavor; Food industries; food processing; food quality; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; kidney beans; lectins; Phaseolus vulgaris; phytohemagglutinin; raffinose; sensory evaluation; snack foods; stachyose; Studies; Sugar; sugar products; sugar-coated; texture
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/j.1750-3841.2006.00176.x

The present study was undertaken to expand the uses of red kidney beans beyond traditional products such as sugar-coated beans--a popular snack food in many Asian countries. Beans were soaked for 12 h (initial temperature 77 °C, end temperature 24 ± 1 °C) and then cooked in boiling water (approximately 99.3 °C) for 14 min. Finally, the cooked beans were sugar-coated by dipping in 20%, 35%, or 50% sugar syrup (w/w) for 45 min at 70 °C and excess syrup was drained at the end of the process. Beans were analyzed for oligosaccharides (raffinose and stachyose) and lectins, as phytohemagglutinating (PHA) activity, at predetermined intervals during processing. A 105-member consumer panel evaluated bean quality for texture, color, sweetness, flavor, and overall acceptability. Most of the weight (81.1% of total) was gained during the 1st h of soaking. There was a significant reduction in raffinose (80.8%) and stachyose (83.4%) after 12 h of soaking. Cooking, which further reduced raffinose for a combined total of 95.8%, had no effect on stachyose. The lectins decreased by about 90% in cooked beans, with over half of inactivation occurring during soaking. On a hedonic scale of 1 to 9 (1 = dislike extremely, 9 = like extremely), all 3 bean samples scored above 5 for all the sensory attributes tested. Beans coated with 50% sugar syrup were rated best overall, with a score of 6.1. Frequency distribution of overall acceptability scores showed that 59% to 70% of the panelists rated different bean samples at a score of 6 or higher.