159 Research Article Received: 31 December 2010 Revised: 20 April 2011 Accepted: 9 June 2011 Published online in Wiley Online Library: 4 August 2011 (wileyonlinelibrary.com) DOI 10.1002/jsfa.4557 Chemical composition, angiotensin-converting enzyme-inhibitory activity and antioxidant activities of few-ﬂower wild rice (Zizania latifolia Turcz.) Bingjun Qian, a,b Yali Luo, a Yun Deng, a,b* Linkui Cao, a Hongshun Yang, c Yongpei Shen d and Jian Ping d Abstract BACKGROUND: The chemical compositions of the stem and leaf sheath of few-ﬂower wild rice were analysed. In addition, their extracts were evaluated for diphenylpicrylhydrazyl (DPPH) free radical-scavenging activity, ferric-reducing antioxidant power and angiotensin-converting enzyme (ACE)-inhibitory activity, since these are important properties of sources of nutraceuticals or functional foods. RESULTS: The stems contained more ascorbic acid (0.06 g kg -1 fresh weight), protein (28.18 g kg -1 dry weight (DW)), reducing sugars (308.54 g kg -1 DW), water-soluble pectin (20.63 g kg -1 DW), Na 2 CO 3 -soluble pectin (44.14 g kg -1 DW), K (8 g kg -1 dry matter (DM), S (6 g kg -1 DM) and P (5 g kg -1 DM) but less starch, total dietary ﬁbre, Si, Na and Ca than the leaf sheaths. The DPPH free radical-scavenging IC 50 values of the stem and leaf sheath extracts were 19.28 and 21.22 mg mL -1 respectively. In addition, the ACE-inhibitory IC 50 value of the stem extracts was 38.54 mg mL -1 . CONCLUSION: Both the stem and leaf sheath extracts exhibited good antioxidant properties, while good ACE-inhibitory activity was detected only in the phosphate buffer solution extracts of the stem. Few-ﬂower wild rice could be processed into formula feeds for ﬁsh, poultry, etc. or functional foods for persons with high blood pressure. c  2011 Society of Chemical Industry Keywords: antihypertensive; antioxidant; chemical composition; few-ﬂower wild rice INTRODUCTION Few-ﬂower wild rice (Zizania latifolia Turcz.) is a fascicular plant grown in fresh water and is mainly distributed in southern China, particularly south of the Yellow River where water, warmth and light are abundant. 1 The edible organ of few-ﬂower wild rice is the swollen gall induced by the parasitic smut fungus (Ustilago esculenta P. Henn.), which is usually harvested in May–June and September–October. The edible stems of few-ﬂower wild rice can be consumed fresh or in processed form as a powder or ﬂour and are considered a good functional food resource. 1 As a result of a signiﬁcant increase in the cultivation area of few- ﬂower wild rice in China, a large quantity of leaf sheath ends up being discarded, and this has become a source of environmental pollution at the cultivation site. As a by-product of few-ﬂower wild rice, leaf sheaths continue to be produced in high amounts. At a rough estimate, the output of dried leaf sheaths is 100 kg per acre of cultivated few-ﬂower wild rice. 2 To date, few authors have investigated the commercial value and functional properties of these leaf sheaths. Cai 3 suggested using them in the cultivation of edible mushrooms. The leaf sheaths are also used as knitting materials after hydrolysis by proteases. 2 In addition, Min 4 and Jin 2 found that the leaf sheaths were rich in dietary ﬁbre and developed a method for extracting this dietary ﬁbre. Furthermore, high amino acid contents were observed in the leaf sheaths by Wang and Feng. 5 In summary, the functional properties of the leaf sheaths of few-ﬂower wild rice have not yet been completely examined or fully exploited. Increasingly, the global population is facing challenges from chronic diseases, including hypertension, dyslipidaemia, type II diabetes mellitus, cardiovascular diseases and some cancers. Evidence has shown the health beneﬁts of high levels of antioxidant compounds in fruits and vegetables in reducing the ∗ Correspondence to: Yun Deng, Department of Food Science and Technology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. E-mail: y deng@sjtu.edu.cn a Department of Food Science and Technology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China b SJTU-Bor Luh Food Safety Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China c School of Cereals, Oils and Foods, Henan University of Technology, 140 Sout Songshan Road, Zhengzhou 450052, China d Shanghai Liantang Jiaobai Co. Ltd, Shanghai 201715, China J Sci Food Agric 2012; 92: 159–164 www.soci.org c  2011 Society of Chemical Industry