SENSORY QUALITIES AND ACCEPTABILITY OF SPINACH GROWN WITH ORGANIC MANURES AND INORGANIC FERTILIZER INPUTS *Jaya Sharma 1 and Sunita Agarwal 2 1 Alankar P.G. Mahila Mahavidyalya, University of Rajasthan, Jaipur 2 Department of Home Science, University of Rajasthan, Jaipur *Author for Correspondence ABSTRACT Spinach (Spinacia oleracea L.) is one of the most popular leafy vegetable crops. It is low in calories and a good source of vitamin C, vitamin A and minerals especially iron. Spinach is greatly responsive to chemicals used in agriculture. Organic farming is a dynamic system of food production. Earthworm decomposes the organic matter into natural soil nutrient which maintain the natural composition of spinach through which sensory attributes develop. To evaluate the acceptability of spinach grown with FYM (T1), Vermicompost (T2), Chemical fertilizer (T3), Vermiculture (T4) and Control (T5) sensory evaluation was conducted on various recipies preferred in Indian kitchen with spinach. The spinach cultivated in vermiculture as well as in vermicompost was preferred more for their texture, colour, taste and flavour attribute than chemically grown spinach in kitchen garden. The organic fertilizers and vermiculture were found to be significantly superior in all sensory parameters and overall acceptability in spinach. Key Words: Vermicompost, Hedonic Scale, Composite Scoring, Vermiculture INTRODUCTION Spinach (Spinacia oleracea L.) is one of the most popular leafy vegetable crops. It is low in calories and a good source of vitamin C, vitamin A and minerals especially iron. Spinach is greatly responsive to nitrogen fertilization (Cantliffe, 1992). Organic agricultural growing systems rely on crop rotations, farmyard manures, composting, mulches and biological pest control to maintain soil productivity and biodiversity, and to control pests. Whereas, in conventional farming farmers apply synthetic fertilizers, herbicides, insecticides, fungicides and pesticides to their crops to provide them with adequate nutrition and to protect them from pest attack and diseases. Such practices are not permitted in organic agriculture. The sensory quality of horticultural products may be influenced by inherent soil composition, cultivar, cultural and management practices, post harvest handling and storage etc. The excessive amount of chemicals can change the appearance as well as composition of horticultural products. These compositional factors fabricate the taste, flavour, texture and colour etc. Organic agriculture is characterized as a system of farming, which focuses on the use of renewable resources and preservation of the environment, but avoids or largely excludes the use of synthetically produced chemicals or fertilizers, herbicides, insecticides, fungicides, or any other pesticides, growth hormones or growth regulators. Vegetables are the part of our diet which gives food maximum variations in taste, colour and flavour. Along with this group supplies energy as well as nutrition for maintenance of body like minerals and vitamins. Taste, colour, flavour are the primary factors to make food acceptable or not. Vegetables can wane their original characteristics very easily because chemicals used in agriculture act after dissolving in their systems. These chemicals can easily deteriorate the composition of vegetables. Spinach is one the most common green leafy vegetable. It contains lots of water and fiber. It can be used in any form like in raw form as salad, in cooked form as vegetable and in processed form as puree. This vegetable is easy to cook and have medicinal as well as nutritional value. The present study was conducted to assess the impact of organic v/s inorganic fertilizer inputs on sensory qualities and acceptability of spinach. 28
MATERIALS AND METHODS Spinach was grown in kitchen garden with various fertilizer inputs FYM (T1), Vermicompost (T2), Chemical fertilizer (T3), Vermiculture (T4) and Control (T5) in kitchen garden at Jaipur city. To assess the acceptability, the present study was conducted in the following phases: Vegetable cultivation Selection and standardization of recipe Threshold test Preparation of recipe Composite scoring Hedonic test Statistical analysis Vegetable Cultivation Spinach crop was cultivated with various treatment inputs. Five seeds of Jobner green variety were sown in earthen pots (30.48 x 30.48 cm). Only one healthy plant was allowed to grow till maturity. Seeds were sown 2.5 cm below the upper layer of soil. Trichoderma was added in the soil of the pots to avoid the disease, Damping off. Crops were raised with recommended doses (as recommended by Department of Horticulture, Government of Rajasthan) of fertilizer inputs. Irrigation was done every day in the evening. In all the organically treated pots only organic pesticide Neemgold was used as pesticide where as in the pots treated with chemical fertilizer, inorganic pesticide was applied. Selection and Standardization of Recipe The recipes of spinach were selected keeping in mind that the taste; colour, and flavour of vegetable express itself clearly. Spinach soup with refined flour (cooked form), Spinach soup without refined flour (cooked form), Palak paneer sabji (cooked form) were selected for sensory evaluation. Recipes were standardized in terms of (ingredient, weight /volume of each ingredient, preparation instruction, cooking time) cooking procedure, serving size and equipment and utensils to be used. Threshold Test Threshold test was used to select the panel members. Threshold test simply indicates the perception of a given stimulus. In the present study threshold test was conducted to determine the sensitivity of members for the basic taste of sweet, sour, salty and control (water) (Table 1). Table 1: Concentration Series of the Substances for Threshold Test S. No. Substance Stock Concentration Concentration Series 1 Sucrose 20 g/100 ml solution 0.4 and 0.6g/100ml 2 Citric acid 1 g/100 ml solution 0.02 and 0.04 g/100 ml 3 Sodium chloride 10 g/100 ml solution 0.08 and0.15 g/100 ml 4 Control water 100 ml water 100 ml water The panel comprised of eighteen persons who voluntarily participated. Threshold test for each taste stimulus were carried out twice. The panel members who could not identify the sweet, sour, salty taste stimulus were disqualified. Preparation of Recipe Spinach was procured from kitchen garden in the morning when the experiment was to be done. According to standardized procedure weighed and measured ingredients were kept at hand. The recipes were prepared according to the time set with judges, when the whole panel was available, so that warm recipies can be served to judge the acceptability and judges can get the perfect taste, flavour, colour, appearance and texture. For the experiment, sample recipe were served to the panelist uniformly warm and in uniform environment (light, surrounding crockery and table ware) and judges can get the perfect taste, flavour, colour, appearance and texture. 29
Composite Scoring Test This test was used to evaluate the taste, colour, flavour, texture and appearance of the vegetable. Samples of each selected recipe were prepared with spinach grown in various organic and inorganic fertilizer inputs and served to the panel of judges to evaluate sensory quality (taste, flavour, colour, texture and appearance). Panel members scored in the composite scoring test sheet (Table 2). A separate scoring sheet was provided for each recipe prepared with various organic and inorganic fertilizer inputs. Table 2: Composite Scoring Test Sheet for Sensory Evaluation Composite Scoring Test Sheet Name Panel No. Date Recipe No. No. Code Taste Colour Flavour Texture Appearances 1 Like extremely 2 Like very much 3 Like moderately 4 Like slightly 5 Neither like or dislike 6 Dislike slightly 7 Dislike moderately 8 Dislike very much 9 Dislike extremely Reason First rinse your mouth with control water in order to become familiar with the taste. Retasting is not allowed. Hedonic Scale Test The most commonly used scale for preference testing is a nine point hedonic scale test. Peryam and Piligrim (1967) defined hedonic scale as a special type of rating scale that measure psychological state directly. The method is actually a measure of acceptability gauged from reaction in terms of their degree of like or dislike for a given set of condition. The panelists were asked to rate the acceptability of the product on a scale, usually of nine point, ranging from like extremely to dislike extremely (Table 3). Statistical Analysis The following statistical analysis was applied to various tests for acceptability. 1. Threshold test: Mean and standard deviation was calculated for the scores given by 18 persons to judge the sensibility of taste. 2. Composite Scoring Test: To judge the effect of various fertilizer on taste, colour, flavour, texture and appearance, ANOVA, f-test was applied to the scores given by panelists. 3. Hedonic scale test: The panelists were asked to rate the acceptability of the product on a scale, usually of nine point, ranging from like extremely to dislike extremely. To evaluate the overall acceptability mean, standard deviation was applied to the scores given by the panelist. 30
Table 3: Nine Point Hedonic Scale Test Sheet for Acceptability Hedonic scale test Name Panel No. Date Recipe No. No. Code Range Acceptability ( the choice) 1 Like extremely 81-90 2 Like very much 71-80 3 Like moderately 61-70 4 Like slightly 51-60 5 Neither like or dislike 41-50 6 Dislike slightly 31-40 7 Dislike moderately 21-30 8 Dislike very much 11-20 9 Dislike extremely 1-10 Reason First rinse your mouth with control water in order to become familiar with the taste. Retasting is not allowed. RESULTS AND DISCUSSION The results of present study are presented here in three phases Threshold Test Composite Scoring Test Hedonic Scale Test Threshold Test This test was performed to select the panel of judges for sensory evaluation. Eighteen persons, who were willing and available at the time of experiment, participated in the threshold test. Threshold tests was carried out twice and recorded for each individual. Eight panel members did not qualify this test. Ten panel members were selected for further acceptability test. Composite Scoring Test In this test five samples of selected recipies were prepared with spinach grown with various fertilizer inputs. The samples were presented to panel of judges and they were asked to give scores for different qualities separately in the test sheets. Spinach Soup with Refined Flour (cooked form). Spinach Soup without Refined Flour (cooked form). Palak Paneer Sabji (cooked form). Spinach Soup (without flour) It can be observed from Table 4 that spinach soup made with vegetable cultivated in organic treatments was found significantly superior over vegetable cultivated in chemical fertilizer and control for colour, taste, flavour and texture of spinach soup. Chemical fertilizer grown spinach registered significant superiority for colour (6.6), taste (6.5), flavour (6.7), texture (6.4) and appearance (6.6) over control. The taste of spinach grown in vermicompost was found significantly superior over vermiculture. Except for taste, all other qualities colour, flavour, texture, appearance of spinach cultivated in vermicompost and vermiculture were found statistically at par (Figure 1). Theuer (2006) was also of the view that the more intense flavors in organic fruits and vegetables probably stem from two factors: somewhat higher average 31
levels of antioxidants, and somewhat lower average crop yields. Yield levels, and the availability of nitrogen to crops, clearly can alter both nutritional and organoleptic quality. Table 4: Impact of Organic Manures, Chemical Fertilizer and vermiculture on Sensory Acceptability in Spinach Soup Treatment Colour Taste Flavour Texture Appearance T1 (FYM) 8.3 7.5 7.6 7.9 7.6 T2(Vermicompost) 8.1 7.8 7.6 8.0 7.8 T3(Chemical Fertilizer) 6.6 6.5 6.7 6.4 6.6 T4(Vermiculture) 8 8.4 7.9 7.9 7.9 T5(Control) 6.2 4.2 4.7 4.7 3.8 S Em ± 0.22 0.21 0.27 0.23 0.23 CD at 5% 0.62 0.61 0.76 0.66 0.64 Figure 1: Spinach Soup Made Spinach Grown in Various Fertilizer inputs Spinach Soup with Flour The texture of spinach soup with flour was found significantly superior in FYM over vermiculture chemical fertilizer and control attaining score 8.2 at 5% level of significance (Table 5). Rest of the qualities colour, taste, flavour and appearance were found at par in all organic fertilizer inputs (Table 5). Spinach cultivated in chemical fertilizer scored for colour (6.8), taste (6.8), flavour (6.5), texture (6.4) and appearance (6.5). Moreira et al., (2003) also concluded that sensorial analysis showed that organically produced Swiss chard retained turgidity, colour and brightness longer than the conventionally produced chard. Table 5: Impact of Organic Manures, Chemical Fertilizer and vermiculture on Sensory Acceptability in Spinach Soup with Flour Treatment Colour Taste Flavour Texture Appearance T1 (FYM) 8.2 7.7 7.7 8.2 7.9 T2(Vermicompost) 7.9 8.2 7.8 7.8 7.9 T3(Chemical Fertilizer) 6.8 6.8 6.5 6.4 6.5 T4(Vermiculture) 8.1 8.1 7.5 7.4 7.8 T5(Control) 4.8 4.5 5.1 4.8 4.0 S Em ± 0.26 0.23 0.29 0.23 0.27 CD at 5% 0.74 0.67 0.82 0.65 0.76 32
Palak Paneer Vegetable Table 6 shows that palak paneer vegetable prepared with chemically cultivated spinach scored for taste (6.5), flavour (6.4), texture (6.7) and appearance (6.6). The colour of spinach in palak paneer vegetable made with spinach grown in chemical fertilizer and control was found statistically at par. Table 6: Impact of Organic Manures, Chemical Fertilizer and vermiculture on Sensory Attributes in Palak Paneer Vegetable Treatment Colour Taste Flavour Texture Appearance T1 (FYM) 8.3 7.5 7.6 7.9 7.6 T2(Vermicompost) 8.1 7.8 8.2 7.6 7.8 T3(Chemical Fertilizer) 6.9 6.5 6.4 6.7 6.6 T4(Vermiculture) 8.4 8.1 8.1 7.9 7.9 T5(Control) 6.2 4.2 4.7 4.7 3.8 S Em± 0.22 0.26 0.26 0.24 0.23 CD at 5% 0.63 0.75 0.75 0.69 0.64 Treatments FYM, vermicompost and vermiculture were found statistically at par to each other for all qualities (colour, taste, flavour, texture and appearance) made with vegetable cultivated organically but found significantly superior over chemical fertilizer and control. Felczyński et al., (2008 ) found wellcoloured beet roots with a low nitrate content were obtained from the zero-fertilization control plots and from the treatment with manure alone at 20 t ha -1. Hedonic Test Spinach soup with flour prepared with spinach grown in vermiculture was liked extremely scored 80.2 (± 0.58 SD). Both FYM and vermicompost were liked very much with scores (79 and 78.6 respectively). Spinach cultivated chemically was accepted as liked moderately (scored 65.6 ± 0.32 SD). Soup prepared with spinach grown in control was liked slightly scored minimum 48 (± 0.92 SD). Spinach soup (without flour) made with organic fertilizer inputs was liked very much (score ranging 71-80) (Table 7). Chemically treated spinach soup was found liked moderately. Palak Paneer vegetable prepared with chemical fertilizer treated spinach was also accepted as liked moderately. Palak Paneer vegetable prepared with spinach grown in vermiculture was liked extremely by the panel members. Spinach grown in FYM and vermicompost were found liked very much. Taiwo et al., (2002) also reported that panelists preferred organically grown okra soup to the chemically grown variant when they assessed the colour, taste, texture and flavour. Organically grown okra enjoyed more acceptability than the chemically grown. Table 7: Impact of Organic Manures, Chemical Fertilizer and vermiculture on Acceptability of Spinach soup with flour, Spinach soup without flour and Palak Paneer Vegetable Spinach soup Spinach soup Palak Paneer vegetable Treatments with flour without flour Scores ±SD Scores ±SD Scores ±SD T1 (FYM) 79 1.29 79 1.29 79 1.29 T2 (Vermicompost) 78.6 0.59 79 0.67 78.8 0.46 T3 (Chemical Fertilizer) 65.6 0.32 66 0.40 65.6 0.42 T4 (Vermiculture) 80.2 0.58 77.8 0.40 80.8 0.52 T5 (Control) 48 0.92 47 0.82 48 0.92 33
Conclusion Since a long time people are enjoying vegetables grown with chemical fertilizers. Chemical agriculture ushered green revolution but only in terms of increased yield but created diverse effects. The produce has destroyed its originality of taste, colour, flavour etc. It can be concluded by the results that spinach grown in vermiculture and vermicompost were found better in taste, colour and appearance in comparison to chemically grown spinach. Overall it is evident from the data that spinach grown organically was more accepted than chemically cultivated spinach in kitchen garden. Organic farming systems with vermiculture biotechnology were the vision of Sir Charles Darwin centuries ago. Earthworm s activity and cast are rich source of nutrient to support plant growth and maintain the composition of horticultural products in natural way. REFERENCES Cantliffe D (1992). Nitrate accumulation in vegetable crops as affected by photoperiod and light duration (beets, radish, spinach, beans). Journal of the American Society for Horticultural Science 97 414-418. Felczyński K and Elkner K (2008). Effect of long-term organic and mineral fertilization on the yield and quality of red beet (Beta vulgaris L.).Vegetable Crops Research Bulletin 68(1) 111 125. Jellineck G (1985). Sensory Evaluation of Food: Theory and Practice. Ellis Horwood Ltd. Chichester, England. Moreira MR, Roura S I and Valle CE (2003). Quality of Swiss chard produced by conventional and organic methods. LWT - Food Science and Technology 36(1) 135 141. Peryam DR and Pilgrim FJ (1957). Hedonic Scale Method of Measuring Food Preferences. Food Technology 9-14. Taiwo LB (2002). Organic okra (abelmoschus esculentus): its growth, yield and organoleptic properties. Nutrition & Food Science 32(5). Theuer RC (2006). Do Organic Fruits and Vegetables Taste Better than Conventional Fruits and Vegetables? The organic center-www.organic-centre.org. 34