SNQ74 JOURNAL OF FOOD SCIENCE—Vol. 69, Nr. 2, 2004 Published on Web 2/20/2004 © 2004 Institute of Food Technologists Further reproduction without permission is prohibited Sensory and Nutritive Qualities of Food JFS: Sensory and Nutritive Qualities of Food Sensory Evaluation of Canned Peach Halves Acidified with Clarified Lemon Juice D. SAURA, N. MARTÍ, J. LAENCINA, V. LIZAMA, AND A.A. CARBONELL-BARRACHINA ABSTRACT: The sensory quality of canned peaches was studied after a year of storage. Citric acid was substituted with 2 different types of lemon juice: turbid (TLJ) and clarified (CLJ). Descriptive and affective tests were carried out using trained and consumer panels of 20 and 30 panelists, respectively. Control canned peaches and those acidified with CLJ obtained statistically equal sensory scores for aroma intensity, juiciness, and overall liking. However, lemon juice–treated peaches were lighter and sweeter than citric acid–treated samples, with differences being more signifi- cant for TLJ. The removal of monoterpenes (especially -terpinene) during the cross-flow filtration of the lemon juice provided a suitable acidifier for peach preservation. Keywords: acidifier, canned fruit, color, juiciness, sensory quality Introduction C anned peaches are one of the most popular canned desserts. Its balance of the sweet and acid tastes and its appearance and texture make the peach a perfect fruit for canning. Spain had a fresh peach production of 183000 t during the 2000-2001 growing season (USDA 2001). During the preservation of peaches, a decrease of the preserva- tion medium pH is necessary. Our goal was to replace citric acid with natural lemon juice, an acidifier perceived by consumers as a more natural or ecological additive. Substances such as -gluconolactone decrease the pH of the medium without having any effect on the aroma profile. Our hypothesis for the current study was that the clar- ified lemon juice would show a behavior similar to that already de- scribed for the -gluconolactone. In addition, because lemon juice was going to be added to the preservation medium of canned peach- es, the effect of this addition on several sensory parameters, such as aroma intensity, color, juiciness, acidity:sweetness ratio, and overall liking, needed to be considered. In 2001, the area of land dedicated to lemon trees in Spain was 43500 ha, with an annual production of about 951800 t; only 20% of this production is dedicated to the food industry (FAO 2001). The selling price of lemons in eastern Spain sometimes does not cover irrigation, pesticides, and picking costs. Thus, there is an impera- tive need for finding new uses for lemons in the food industry be- cause otherwise this agricultural and industrial sector is going to collapse, with all the implications that this breakdown can have in the agriculture, industry, and culture of eastern Spain. Therefore, in this experiment, canned peaches acidified with clarified lemon juice were prepared with the main general objec- tives of finding (a) a more “natural” product that fits the new mar- ket for ecological products and (b) new alternatives for using lem- ons. The main expected problems (decreasing the quality of canned peaches) were related to the amount and nature of the monoterpe- nes added to the peaches through the addition of the lemon juice (especially -terpineol) and their effects on the aroma intensity and overall quality. The effects of lemon juice on color, juiciness, and acidity:sweetness ratio were studied as well. Our hypothesis was that tangential-flow or cross-flow filtration of the lemon juice would significantly reduce the amount of undesirable monoterpe- nes (aroma) and some sweet compounds (acidity:sweetness ratio), therefore providing a new way of controlling the pH in canned products without loss of sensory quality. Materials and Methods Fruit material The variety of peach chosen for the current experiment, Sudanell, has a free stone, uniform and large size, symmetric shape, yellow pulp, and firm but melting texture. This selection has other implications, as well; in general, freestone peaches are recog- nized as more aromatic than clingstone peaches. Peaches were grown in northeastern Spain (Lleida, Catalonia) and had a total soluble solids concentration between 9.6 and 10.4 °Brix and a pH between 3.61 and 3.65. Clarification of lemon juice The clarified juice was obtained by the tangential- or cross-flow filtration method described by Saura and others (1991). Experi- ments were performed on a Minitan cross-flow filtration unit (Mil- lipore, Bedford, Mass., U.S.A.) equipped with 4 Durapore cartridg- es of 0.45 m pore diameter. Each cartridge provided 0.24 m 2 membrane area. The unit was operated as a recirculating batch system, so both retentate and permeate streams were recirculated back into the feed tank. Feed stream was pumped from a temper- ature-controlled tank, 30  2 °C, into the filtration cartridges at a rate of 0.5 L/min. Ultrazym 100 G (Novo Nordisk, Kobenham, Den- mark) was added to the feed tank at a concentration of 500 mg/L; this is an enzyme mixture with pectin methyl-esterase activity, which will degrade the pectin substances, and finally the degraded substances will flocculate as calcium salts. A valve in the return line controlled transmembrane pressure. MS 20030089 Submitted 2/18/03, Revised 8/1/03, Accepted 11/19/03. Authors Saura, Martí, and Lizama are from Unidad Mixta IBMC – FMC FoodTech, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Carretera de Beniel, Km 3.2, 03312-Orihuela, Alicante, Spain. Author Laencina is from Departamento de Tecnología de Alimentos, Facultad de Veterinaria, Universidad de Murcia, Campus Universitario de Espinardo, 30071 Murcia, Spain. Author Carbonell-Barrachina is from División Tecnología de Alimentos, Universidad Miguel Hernández, Carretera de Beniel, km 3.2, 03312-Orihuela, Alicante, Spain. Direct inquiries to author Carbonell-Barrachina (E-mail: angel.carbonell@umh.es).