C: Food Chemistry Effect of Storage on the Physico-Chemical and Antioxidant Properties of Strawberry and Kiwi Leathers Anibal A. Concha-Meyer, Valeria D’Ignoti, Barbara Saez, Ricardo I. Diaz, and Carolina A. Torres Abstract: Strawberry and kiwi leathers were used to develop a new healthy and preservative-free fruit snack for new markets. Fruit puree was dehydrated at 60 °C for 20 h and subjected to accelerated storage. Soluble solids, titratable acidity, pH, water activity (a w ), total phenolic (TP), antioxidant activity (AOA) and capacity (ORAC), and color change (browning index) were measured in leathers, cooked, and fresh purees. An untrained panel was used to evaluate consumer acceptability. Soluble solids of fresh purees were 11.24 to 13.04 °Brix, whereas pH was 3.46 to 3.39. Leathers presented an a w of 0.59 to 0.67, and a moisture content of 21 kg water/100 kg. BI decreased in both leathers over accelerated storage period. TP and AOA were higher (P 0.05) in strawberry formulations. ORAC decreased 57% in strawberry and 65% in kiwi leathers when compared to fruit puree. TP and AOA increased in strawberries during storage. Strawberry and Kiwi leathers may be a feasible new, natural, high antioxidant, and healthy snack for the Chilean and other world markets, such as Europe, particularly the strawberry leather, which was preferred by untrained panelists. Keywords: antioxidant, fruit leather, kiwi, storage, strawberry Introduction Fruit leathers represent a different method of fruit preservation and they have become an alternative to take advantage of fruit surplus by adding value and diversifying fruit consumption op- tions. Originally, these fruit snacks were homemade developed as an alternative preservation method and only in recent years have emerged as an industrial manufactured healthy product with a considerable nutritional value (Raab and Oehler 2000; Quintero Ruiz and others 2010; Torres and others 2015). Fruit leathers are obtained by fruit puree concentration and de- hydration, and naturally contain acids, sugars, and high metoxy- lation jellifying pectins. They can include other additives in their formulation such as different sugars, sodium bisulfite (Quintero Ruiz and others 2012), powdered milk, soy proteins to increase total solids (Gujral and Khanna 2002), maltodextrin, soy lecithin, hydrogenated palm oil and egg yellow as coloring agent and solu- ble starch (Jaswir and others 2008), wheat flour, pectin and anti- browning agents (Vijayanand and others 2000). Formulation of fruit leather can include different fruits such as apples, jackfruit, berries, grapes, kiwis, banana, oranges, apricots, pineapples, papayas, peaches, pears, tomatoes, and also fruit mixes. The dehydrating process allows obtaining flexible, chewable, and rich leathers that are also nutritious. This snack can be considered a healthy option because it is low in calories (<100 kcals each 14 g serving) and is a good source of vitamins, antioxidants, and fiber from fruit (Huang and Hsieh 2005; Phimpharian and others 2011; Torres and others 2015). Moreover, some studies demon- strated that fruit consumption is linked to prevention and risk decrease of chronic cardiovascular diseases, high arterial pressure, MS 20151571 Submitted 9/16/2015, Accepted 12/12/2015. Authors Concha- Meyer, D’Ignoti, Saez, and Diaz are with Centro de Estudios en Alimentos Procesados (CEAP), Avenida San Miguel #3425, Talca 3480137, Chile. Author Torres is with Centro de Pom´ aceas, Univ. de Talca, Av. Lircay s/n, Talca 3480137, Chile. Direct inquiries to author Torres (E-mail: cartorres@utalca.cl) diabetes, and some types of cancer (Krauss and others 2000; Byers and others 2002). Thus, currently, there is an increasing interest on research and development of this product in different countries (Huang and Hsieh 2005; Okilya and others 2010). Azeredo and others (2006) developed a mango leather with no preservatives, which was shelf- stable during 6 mo using a combination of low a W (0.62) and low pH (3.8) in the final product. Strawberry, kiwi, and apple fruits are considered to be functional fruit, due to their high antioxidant content, and the presence of high amount of specific phenolic compounds (Costa and others 2006; Cerezo and others 2010; Torres and others 2015). Because currently literature provides scarce information on the development and physicochemical evaluation of preservative-free kiwi and strawberry leathers, the purpose of this work was to study the physicochemical, microbiological, and organoleptic properties of different leather formulations during storage in order to assess their potential to become a new and healthy snack in the market. Materials and Methods Materials Apples (Malus domestica Borkh. L. cv Fuji), strawberries (Fra- garia Chiloensis, L. Mill), kiwi (Actinidia Chinensis, Planch.), and commercial stevia (Stevia Rebaudiana, Bertoni) sweetener (Daily, Santiago, Chile) were purchased in local markets in Talca, Chile. Production of fruit leather Whole apples and kiwis were weighed, washed, and disinfected in 5 ppm sodium hypochlorite solution for 5 min, then rinsed in water. Whole apples were cut into 1 cm 2 cubes discarding the core and the seeds, whereas kiwis were peeled and cut into 1 cm 2 cubes. Frozen strawberries were thawed, washed, and then cut into 1 cm 2 cubes. Formulations considered 40% apples and 60% of strawberries or kiwi as treatments based on previous trials (Torres and others C  2016 Institute of Food Technologists R  doi: 10.1111/1750-3841.13214 Vol. 81, Nr. 3, 2016  Journal of Food Science C569 Further reproduction without permission is prohibited