S: Sensory & Food Quality JFS S: Sensory and Food Quality Relation between Developmental Stage, Sensory Properties, and Volatile Content of Organically and Conventionally Grown Pac Choi ( Brassica rapa var. Mei Qing Choi) MARTIN TALAVERA-BIANCHI,KOUSHIK ADHIKARI,EDGAR CHAMBERS IV, EDWARD E. CAREY, AND DELORES H. CHAMBERS ABSTRACT: This study was conducted to identify and quantify the sensory characteristics and chemical profile of organically and conventionally grown pac choi (Brassica rapa var. Mei Qing Choi), also called bok choy, at 3 stages of growth (2.5, 4.5, and 6.5 wk). Sensory and instrumental data were correlated using partial least squares regression. Pac choi was grown in late spring. Descriptive sensory analysis was conducted by a highly trained panel and compounds were identified and quantified using a gas chromatograph/mass spectrometer. The findings of the study indicate that the differences in sensory characteristics and chemical profiles among stages of growth are more substantial than the differences between organic and conventional production. Green-unripe, musty/earthy, let- tuce, and sweet flavors are representative in pac choi at early stages of growth. When older, pac choi has higher intensities of green-grassy/leafy, bitter, cabbage, and sulfur flavors that are associated with the increase of (Z)-3- hexen-1-ol, octyl acetate, 1-nonanol, 2-decanone, 1-penten-3-ol, linalool, camphor, menthol, isobornyl acetate, ger- anylacetone, and cedrol compounds. Conventional pac choi was higher than organic pac choi in green overall, bitter, and soapy flavors only at 2.5 wk of age. This may be associated with the presence of (Z)-3-hexenal, 2-hexyn-1-ol, and (E)-2-hexenal compounds. Practical Application: The increased popularity of organic production has amplified the need for research that will help in understanding how this production system affects the final quality of food products. This study suggests that the stage of development has a much larger impact on sensory quality than organic or conventional growing of pac choi. Findings from this study promote consumer choice by showing that comparable sensory quality can be ob- tained using either production system, making the ultimate choice not only based on sensory quality but consumer choice related to environmental beliefs or economics. Keywords: bok choy, organic, pac choi, sensory, volatiles Introduction O rganic foods often are promoted as being more environmen- tally friendly. Crop rotation, cover crops, and natural prod- ucts (such as natural fertilizes and pesticides) are used to enhance or maintain long-term soil fertility, minimize pollution, avoid syn- thetic fertilizers and pesticides, consider the social and economic impact, and produce higher quality products (Bourn and Prescott 2002; Winter and Davis 2006). However, results at this point seem inconsistent and show no clear trends or patterns regarding the effects that organic fertilization have on the crops’ final quality (Basker 1992; Bourn and Prescott 2002). Those inconsistencies may exist because the differences between organic and conventional practices are product specific (Fillion and Arazi 2002) or because differences are dependent on confounding factors such as age, picking time, or transportation. MS 20090596 Submitted 6/25/2009, Accepted 2/2/2010. Author Talavera- Bianchi is with PepsiCo Inc., Sensory & Consumer Sciences, Barrington, IL 60010, U.S.A. Authors Adhikari, Chambers IV, and Chambers are with The Sensory Analysis Center, Dept. of Human Nutrition, Justin Hall, Kansas State Univ., Manhattan, KS 66506, U.S.A. Author Carey is with Dept. of Hor- ticulture, Forestry, and Recreation Resources, Throckmorton, Kansas State Univ., Manhattan, KS 66506, U.S.A. Direct inquiries to author Chambers (E-mail: delores@ksu.edu). Pac choi (Brassica rapa var. Mei Qing Choi) is a variety of Chi- nese cabbage, well known in Asia, that is gaining popularity in the United States. The flavor of pac choi has been previously studied by Schnitzler and Kallabis-Rippel (1998). Those authors studied differ- ent varieties of cooked and fresh pac choi using a trained sensory panel. Descriptive terms used by these authors were sweet, sour, bitter, spicy, and cabbage-like. Other studies focused on instru- mental analysis of pac choi leaves to evaluate flavonoid composi- tion (Rochfort and others 2006), phenolic content in organic plants (Young and others 2005), and the effect of packaging on their shelf life (Lu 2007). However, stage of development was not included in these studies. Stage of development at the time of harvest should be included when evaluating pac choi because this plant is frequently consumed at different maturity levels (that is, baby or mature stage) (Rochfort and others 2006). Plant maturity at the time of harvest is critical for flavor and tex- ture development (Mattheis and Fellman 1999). It has been sug- gested that age has an effect on the content of flavor compounds such as catechins and amino acids, which tend to create off-flavors in young tea leaves (Kinugasa and others 1997). It also has been sug- gested that some fruits such as muskmelon must be harvested at their ripening stage for best postharvest quality (Asghary and oth- ers 2005). Tomatoes, where harvest maturity is a critical factor re- lated to sensory properties, have been the object of many studies to C  2010 Institute of Food Technologists R  Vol. 75, Nr. 4, 2010—JOURNAL OF FOOD SCIENCE S173 doi: 10.1111/j.1750-3841.2010.01585.x Further reproduction without permission is prohibited