Organic Versus Conventional – a Comparative Study on Quality and Nutritive Value of Selected Vegetable Crops of Southern India

SAARC J. Agric., 18(1): 99-116 (2020) DOI: https://doi.org/10.3329/sja.v18i1.48385 Research Article ORGANIC VERSUS CONVENTIONAL – A COMPARATIVE STUDY ON QUALITY AND NUTRITIVE VALUE OF SELECTED VEGETABLE CROPS OF SOUTHERN INDIA J.R. Xavier*, V. Mythri, R. Nagaraj, V.C.P. Ramakrishna P.E. Patki and A.D. Semwal Defence Food Research Laboratory, Defence Research and Development Organization, Siddharthanagar, Mysore- 570 011, India ABSTRACT Vegetables are defined as edible plant parts generally consumed raw or cooked with a main dish, in a mixed dish, as an appetizer or as a salad. Food safety aspects related to microbial quality (total plate count, yeast and mold and food borne pathogens) and toxic residue (heavy metals) and mineral content were investigated for vegetables such as green leafy vegetable, salad vegetables, sprouts, brinjal, green chilies and French beans collected from organic and conventional outlets from Mysore region, Karnataka, India. Microbial analysis was carried out using standard procedures and mminerals (Ca, K, Fe, Cu, Mg, Mn and Zn) and heavy metals (Cd and Pb) were determined. Significant variations (p>0.05) were observed for microbial quality among organic and conventional vegetables. Mineral and vitamin C content were also significantly higher (p>0.01) in organic samples. Heavy metal contamination for lead and cadmium tested positive for conventional samples while organic samples tested negative. The variables that contributed most for the variability were heavy metal contamination, mineral and vitamin C content. Organically grown vegetables were free from heavy metals and safe for consumption, as well as they are rich in mineral and vitamin C content in comparison to conventional samples. Keywords: Conventional vegetables, Microbial safety, Nutrition, Organic vegetables, Toxic residues. INTRODUCTION Vegetables are fresh and edible portion of herbaceous plants and form integral part of a balanced diet, utilized to build up and repair the body. Being a rich source of vitamins, minerals and dietary fiber vegetables also contain valuable food ingredients * Corresponding author: Received: 20.03.2020 Accepted: 28.06.2020 100 Xavier et al. (Eni et al., 2010). Antioxidant in vegetables is some of the important nutrients besides other vitamins, minerals, flavonoids and photochemical, which have been reported to contribute to health. Their consumption not only prevents us from many diseases but also provides taste and variety to the diet. Vegetables play a major role in increasing appetite, improve digestion and also provide valuable roughages which help in bowel movement of intestine and neutralize acids. Mysore is located in southern boundary of Karnataka state. Vegetables grown in different types of cultivation differ in quality microbial and nutritive quality as per earlier reports. Organic farming can be defined as an ecological production system that promotes and enhances biodiversity and biological cycle in soil, crop and livestock. Organic products are considered as safe for environment and human health (Somasundram et al., 2016). Heavy metal contamination of the food items is one of the most important aspects of food quality assurance. Vegetables can absorb metals from soil as well as from deposits on the parts of the vegetables exposed to the air from polluted environments (Shahid et al., 2016). Heavy metals are not biodegradable, have long biological half-lives and accumulate in different body organs leading to unwanted side effects. Lead and cadmium are among the most abundant heavy metals and are particularly toxic which leads to disruption of numerous biological and biochemical processes in the human body. The present study was carried out to evaluate the food safety aspects related to microbial quality (total plate count, yeast and mold and specific food borne pathogens), heavy metals (Cd and Pb) and mineral content (Ca, Na, K, Fe, Cu, Mg, Mn and Zn) of organically and conventionally cultivated vegetables such as green leafy vegetable, salad vegetables, sprouts (green gram, Bengal gram and horse gram), brinjal, green chilies and French beans collected from organic and conventional outlets from Mysore region, Karnataka, India. The vegetables were grouped into five major categories such as green leafy vegetables, salad vegetables, other vegetables, sprouts and protected cultivated vegetables. MATERIALS AND METHODS Sample collection, storage and preparation A total of 145 fresh samples including 12 types of vegetables and 03 sprouts namely green leafy vegetables (GLV) such as amaranthus, coriander, fenugreek leaves, mint and palak, salad vegetables such as cucumber, cabbage and tomato, green chilli, cauliflower, French beans and brinjal were collected from certified outlets selling organic and conventionally grown vegetables from city of Mysore, Karnataka (12.2958° N, 76.6394° E) (Table 1). The samples were collected over a period of five months (January to May, 2018). The samples collected were separately packed in polythene bags, labeled with codes and brought immediately to laboratory. The organic samples were labeled with codes prefixed with letter ‘O’ while the conventionally samples were labeled with codes prefixed with letter ‘C’ followed by name and number of samples collected. 101 ORGANIC VERSES CONVENTIONAL VEGETABLE PRODUCTION Table 1. Conventional and organic samples collected from Mysore Sl. No. Sample (A) 1. Green leafy vegetables (GLV) Amaranthus Amaranthus gangeticus 2. Coriander Coriandrum sativum 3. Fenugreek leaves Trigonella foenum 4. Mint leaves Mentha spicata 5. Palak Spinacia oleracea (B) Scientific name Sample code Method CA01 OA01 CCR02 OCCR02 CFE03 OFE03 CM04 OM04 CPA05 OPA05 Conventional Organic Conventional Organic Conventional Organic Conventional Organic Conventional Organic CCB07 Conventional OCB07 Organic CCC08 Conventional OCC08 Organic CT09 Conventional OT09 Organic CGC1O Conventional OGC10 Organic CFB11 Conventional Salad Vegetables 1. 2. 3. (C) Cabbage Cucumber Tomato Brassica oleracea Cucumis sativus Lycopersicone sculentum Other Vegetables 1. Green chilli Capsicum annum 2. French beans Phaseolus vulgaris OFB11 Organic 3. Cauliflower Brassica oleracea var. botrytis CCF12 Conventional OCF12 Organic 4. Brinjal Solanum melongena CBJ13 Conventional OBJ13 Organic (E) Sprouts 1. Bengal gram Cicer arietinum SBG1 Conventional 2. Green gram Vigna radiata SHG2 Conventional 3. Horse gram Macrotyloma uniflorum SGG3 Conventional Broccoli Brassica oleracea var. italic PBR06 Protected Strawberry Fragaria ananassa PSB14 Protected Protected cultivation 102 Xavier et al. Microbial Analysis Fifty grams of each sample were placed inside a sterile plastic bag with 450 mL of 0.1% buffered peptone water (BPW), and gently rubbed for 1 min. Mesophilic aerobic bacteria, total coliforms and yeasts and molds were enumerated (...truncated)