Physico-Chemical and Sensory Quality Criteria of Green Beans ( Phaseolus vulgaris , L.) C. Martínez*, G. Ros, M.J. Periago, G. López, J. Ortu ˜ no and F. Rincón C. Martínez, G. Ros, M.J. Periago, G. López, J. Ortu ˜ no: Department of Food Science, Veterinary Faculty, University of Murcia, E-30071 Murcia (Spain) F. Rincón: Department of Food Science, Veterinary Faculty, University of C´ ordoba, E-30100 C ´ ordoba (Spain) (Received September 5, 1994; accepted February 23, 1995) Two varieties of green beans ( Phaseolus vulgaris L .), one round and the other flat at different stages of maturity were analysed for nine physico-chemical and seven sensory variables. Moisture content, chlorophyll, alcohol insoluble solids, soluble solids and total acidity were found to be of relevance for measuring the growth and maturity of round green beans. A lcohol insoluble solids, soluble solids, and total acidity increased significantly during development, while moisture and chlorophyll showed an opposite trend. Fibrousness, juiciness and hardness were the most important sensory variables for the overall acceptance of the cooked product. Multi-dimensional scaling revealed a weak relationship between the sensory attributes and the physico-chemical variables which define maturity. ©1995 Academic Press Limited Introduction Quality is one of the most defined terms in use in the food industry today but it is also perhaps one of the most confusing because it is used for several distinct purposes. The most widely used concept is the fitness for purpose sense which relates to the ability of a product to satisfy a given need (1). The quality of many processed fruits and vegetables is markedly influenced by the physiological maturity of the raw materials at the time of harvest. This maturity is often determined by visual inspection, but in quality control, there is a need to have objective methods for quality determination (2,3). Alcohol insoluble solids, soluble solids, moisture content, colour and tenderometer value have been found of relevance for measuring pea growth and maturity (4). Legumes hold an important place in the Mediterranean diet, providing a high level of energy from carbohydrates and proteins and a low level of energy from fats. A remarkable increase in the con- sumption of green legumes has occurred in the Medi- terranean countries over the last few years, mainly due to the availability of frozen legumes (5). The green bean ( Phaseolus vulgaris L.) is relatively fast maturing crop in which the whole seed pod is harvested immature for processing by canning and freezing. The length of the developing seed within the pod has proved the most satisfactory method for measuring maturity (6), how- ever, physico-chemical changes have been given little attention in the literature. Sensory attributes (appearance, texture, aroma and flavour) are a function of the physico-chemical compo- sition of the vegetable (7), which is influenced by the quality and composition of the raw materials. By determining which product sensory attributes are most important to consumers, we can focus development efforts on satisfying their expectations (8). Knowledge of relationships between food composition and sensory attributes has been helpful in selection of better sweet corn genotype for the food industry (9), in prediction of sensory quality from physico-chemical measurements in frozen peas (10), or simply in the commercial classification of canned grapefruit based on analytical and sensory properties (11). The main purpose of this paper was to study the physical and chemical changes in two varieties of green bean to predict their maturity level. The second aim was to obtain consumer acceptance data and explore correlations between sensory and instrumental results using multi-dimensional scaling. Materials and Methods M aterials Two cultivars of green bean ( Phaseolus vulgaris L.) one round (STRIKE) and the other flat (BINA) (Asgrow Seed Company, Barcelona, Spain) were grown in a greenhouse and hand harvested in June 1992 at the Agricultural Experimental Centre of the University of Murcia (southeast Spain). STRIKE cultivar was classi- fied by pod diameter following the Seed Company’s recommendations into four sizes: 1 ( ≤ 6.5 mm), 2 (from 6.6 to 8 mm), 3 (from 8.1 to 9 mm) and 4 (from 9.1 to *To whom correspondence should be addressed. Lebensm.-Wiss. u.-Technol., 28, 515–520 (1995) 0023-6438/95/050515 + 06 $12.00/0 ©1995 Academic Press Limited 515