S: Sensory & Food Quality JFS S: Sensory and Food Quality Changes in Postharvest Quality of Swiss Chard Grown Using 3 Organic Preharvest Treatments N. DAISS, M.G. LOBO, AND M. GONZALEZ ABSTRACT: Using storage conditions recommended for conventional chard (4 ◦ C, 90% RH and 7 d), the chard treated with some organic preharvest treatments [effective microorganisms, a fermented mixture of effective mi- croorganisms with organic matter (EM–Bokashi + EM), and an auxiliary soil product] lost considerable water (> 2%) and weight (> 25%). These results indicate that organic methods tested produce a vegetable that can not sustain its quality when commercialized through the conventional supply chain. Nevertheless, respiration, color, pH, and titratable acidity practically remained constant during conservation. Ascorbic acid content was constant in chard treated with the different preharvest treatments and collected at 8 wk after sowing (normal harvest). However, the ascorbic acid content of the control chard decreased 60% after 7 d of storage. This vitamin diminished (35%) in chard collected after 19 wk after sowing (late harvest) during the postharvest conservation. The greatest difference in chard quality was registered between sampling dates since chard collected during the late harvest had higher levels of dry matter, sugars, acids, proteins, and ascorbic acid than chard collected during the normal harvest. Keywords: auxiliary soil product, Beta vulgaris L. var. cycla L., Bokashi, effective microorganisms, organic production Introduction S wiss chard (Beta vulgaris L. var. cycla L.) is a very perishable veg- etable that has to be either consumed within a few days after harvest or submitted to preservation methods in order to extend its shelf life. Quality of fresh Swiss chard leaves is highly dependent on the temperature and humidity of the storage atmosphere (Roura and others 2000a). Fresh Swiss chard was stored at 4 or 18 ◦ C and 43%, 86%, or 98% relative humidity (RH). Leaf quality was unac- ceptable after 3 d of storage at 18 ◦ C, regardless of RH level. Leaves stored at 4 ◦ C and 86% or 98% RH remained acceptable for 9 d. Leaves stored at 4 ◦ C and 43% RH were unacceptable after 4 d of storage due to dehydration. Low temperature and high RH delayed weight, water, and chlorophyll losses, and helped to maintain sen- sory attributes. In recent years, there is a growing interest in organic foods be- cause consumers desire healthier and safer foods (Sloan 2002). Because organic plants are grown without the aid of chemical- synthetic pesticides and largely without the use of readily solu- ble mineral fertilizers (European Union 1991), differences between these foods and conventional products should be expected. Expo- sure to different chemicals, different nutrients, and different cul- tivation methods may affect postharvest quality. For this reason, organic products might require different preservation technologies from those employed with the conventional products to be fresh marketed. However, as Magkos and others (2006) highlighted, most studies related to organic production have focused on cultivation and harvesting, while there is relatively little published research about postharvest processing conditions. The storage shelf life of Swiss chard produced by conventional and organic methods and stored at 4 ◦ C and 98% RH for 25 d has been studied (Moreira and MS 20080094 Submitted 2/6/2008, Accepted 4/29/2008. Authors are with In- stituto Canario de Investigaciones Agrarias, Tropical Fruits Dept., P.O. Box 60, 38200 – La Laguna, Spain. Direct inquiries to author Gonzalez (E-mail: mgonzal@icia.es). others 2003). Water content, chlorophyll content, pH, and titratable acidity were also similar for organic and conventional chards. How- ever, sensory analysis showed that organic chard retained turgidity, color, and brightness longer than conventional chard. Organic farming involves different cultivation practices and a limited use of nonsynthetic fertilizers and auxiliary soil products. Inoculating the soil/plant ecosystem with effective microorganisms [(EM), a fermented mixed culture of phototrophic bacteria, lactic acid bacteria, and yeasts in acidic medium] or a mixture of EM and fermented organic matter (EM–Bokashi) can improve the growth, yield, and quality of crops and enhance the physical and chemical properties of soil (Yan and Xu 2002; Goh 2003; Hammes 2003). Aux- iliary soil products can help improve the texture of the soil. When the organic material contained in these products decomposes, it aerates the soil, making it less compact. Moreover, these prod- ucts increase microbiological activity, favoring the bio-availability of nutrients that accumulate in the soil in a form that cannot be as- similated by the plant (due to the continuous use of fertilizers and pesticides). The main objective of this study was to evaluate the effect of dif- ferent organic preharvest treatments on the postharvest quality of Swiss chard to verify whether or not these organic methods produce a vegetable that sustains its quality when commercialized through the conventional supply chain. The organic treatments evaluated were EM, a mixture of EM with fermented organic matter, and an auxiliary soil product. Materials and Methods Experimental field, crop conditions, and plant material The study was carried out using organic production standards established in Council Regulation (EEC) 2092/91 (European Union 1991) and its subsequent modifications. The experiments were car- ried out in a 300 m 2 organic field located at Los Silos in the north of Tenerife (Canary Islands, Spain). The field, located 111 m above sea S314 JOURNAL OF FOOD SCIENCE—Vol. 73, Nr. 6, 2008 C  2008 Institute of Food Technologists R  doi: 10.1111/j.1750-3841.2008.00842.x Further reproduction without permission is prohibited