Studies on sensory evaluation and microbial count of osmodried karonda (Carissa carandas L.)

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1 Asian J. Dairy & Food Res., 4() 05: 4-45 Print ISSN: / Online ISSN: AGRICULTURAL RESEARCH COMMUNICATION CENTRE Studies on sensory evaluation and microbial count of osmodried karonda (Carissa carandas L.) L. Suhasini*, K. Vanajalatha, A.S. Padmavathamma and P. Vekateshwar Rao Department of Horticulture, College of Horticulture, Dr. Y.S.R. Horticultural University, Rajendranagar, Hyderabad , India. Received: Accepted: DOI: / ABSTRACT A Study was undertaken during 0-04 at post harvest technology laboratory, College of Horticulture, Rajendranagar, Hyderabad, to study the sensory evaluation and microbial count of osmo-dried karonda.the osmotic dehydration of karonda was studied with two concentrations of salt viz. % and 5%NaCl with three different durations of dipping times viz., and. After osmosis of the karonda slices in the salt solutions these were laid on the hot air oven for dehydration. After osmotic dehydration, the products were packed in high density polyethylene bags and stored in ambient temperature for a period of 4 months. The microbiological changes of the products were evaluated and a taste panel evaluated the organoleptic quality of the products during the storage period. Minimum microbial count (.00) was recorded for osmosis in 5% NaCl solution for. The product of 5%NaCl solution for when stored 4 months at room temperature secured highest sensory score (8.05). Key words: Karonda,Microbial count, Osmo-dried, Sensory evaluation. INTRODUCTION Karonda (Carissa carandas L) belonging to the family Apocynaceae. Karonda is an evergreen deciduous small to big shrub usually -4 m tall. The stem is rich in white latex and the branches contain sharp spines. The fruit is a berry, which is formed in clusters of -0 fruits.the fruit is globose to broad ovoid in shape and contains many seeds. Young fruits are pinkish white and become red to dark purple when ripe. Ripe fruit color vary from white, green and pinkish red depending on the genotype (Malik et al., 00).Karonda is highly drought tolerant plant, it thrives well in wide range of soils including waste lands and problematic soils. It can be grown for making beautiful juvenile hedge and the presence of axillary spines it can be a very good bio-fence (Sharma and Banyal, 00). Osmotic dehydration is one of most important complementary treatment and food preservation technique in the processing of dehydrated foods, since it presents some benefits such as reducing the damage of heat to the flavor, color, inhibiting the browning of enzymes and decrease the energy costs (Alakali et al., 006 ). This osmotic dehydrated food is utilized to produce the concentrates of vegetables and fruits. Osmotic dehydration has gained attention recently due to its potential application in the food processing industry. It is a useful technique for the production of safe, stable, nutritious, tasty, economical and concentrated food obtained by placing the solid food, whole or in pieces in sugar or salt aqueous solution of high osmotic pressure (Fito et al., 00). MATERIALS AND METHODS The experiment was conducted at the Processing Laboratory, Department of Fruit Science at Dr. Y.S.R. Horticultural University, College of Horticulture Rajendranagar, Hyderabad during the year Flow chart for osmotic dehdyration of karonda Selection of hard ripe fruits Washing Slice the fruit into two equal parts Remove seeds Salt solution preparation Osmotic treatment *Corresponding author s chinni8@gmail.com, Dept. Horticulture, Venkatramanna gudem, West Godavari Dist. Dr.Y.S.R. H.U. E mail: dsa@drysrhu.edu.in, Dr.P. Venkateshwar rao. Head of Crop Physiology, College of Agriculture, Rajendranagar, Hyderabad. pvraophy@gmal.com.

2 4 ASIAN JOURNAL OF DAIRY AND FOOD RESEARCH Draining Hot-air oven drying Packaging Storage TREATMENTS: T D : Dipping in % NaCl for, T D : Dipping in % NaCl for, T D : Dipping in % NaCl for, T 4 D 4 : Dipping in 5% NaCl for, T 5 D 5 : Dipping in 5% NaCl for, T 6 D 6 : Dipping in 5% NaCl for, T 7 D 7 : Control (Dip in 0.% KMS + 0.% SB for 0 min) From T to T 6 all treatments contain 0.% KMS + 0.% SB+ 0.% Citric acid but Control contain only 0.% KMS + 0.% SB. Parameters: Sensory evaluation of the product: Organoleptic quality evaluation of osmotically dehydrated Karonda slices was done initially after drying of the sample and subsequently after and 4 months of storage. The various sensory features of the dehydrated samples was done by a panel of skilled judges by adopting a hedonic rating system having 00 points and score for quality parameters was 0 for colour and texture; and 40 for flavour. Microbial count in dehydrated slices: For estimating the total microbial population in different sample products, dilution plate method was followed. One gram of sample was thoroughly mixed in nine ml of sterile saline water. One ml of sample was transferred through a sterile pipette to a screw cap tube containing nine ml of sterile saline water. This gave 0ɲ i.e. 0.0% concentration. Similarly serial dilutions were made ml of the serially diluted sample was placed in the sterile petri dish to which cooled plate count agar medium was added and mixed thoroughly with the suspension and then allowed to set and then incubated at 8+p C for 48hrs. Individual colonies were counted and multiplied with the dilution factor to get the microbial population in gm of sample. The data from study was subjected to analysis in a Completely Randomized Design (CRD) with Factorial concept RESULTS AND DISCUSSION Sensory evaluation: Significant difference was observed between the s and duration of dipping times. The interaction between and duration of dipping was found to be significantly different. The highest sensory score was obtained in 5%NaCl concentration and of dipping time. Osmotically dehydrated slices were evaluated for their sensory qualities. Sensory scores obtained for color, texture, flavour as well as overall acceptability from osmosed karonda slices at different stages of storage. It would be appropriate to mention at the beginning that the obtained overall acceptability scores in the range of is very good; is good; 0-59 is average and 0-9 is poor. At initial month of storage: The various osmotic pretreatments significantly affected the sensory score for color and it was highest (6.) in treatment T 6 while the minimum value (9.4) for T and (5.7) value obtained for control sample (T 7 ). In osmotically dehydrated samples score varied from 9.4 to 6. which was in acceptable to highly acceptable range (Table ).In osmotically dehydrated samples score for texture ranged from.80 to 7.. The highest score (7.) was observed in T and minimum score (4.56) was observed in case of control slices (T 7 ) (Table ). Data pertaining to sensory score for flavor, there was a significant difference found between s and duration of dipping times. It was highest (8.40) in treatment T 6 while the minimum value (.40) for T and 4.50 value obtained for control sample (T 7 ). In osmotically dehydrated samples score varied from.40 to 8.40 which was in acceptable to highly acceptable range (Table ).Statistically significant variations due to different s and dipping times were observed with respect to score for overall acceptability. Effect of different osmotic treatments indicates that karonda slices made using 5%NaCl for (T 6 ) rated significantly superior (8.05) and followed by T 5. The minimum score was observed in control (44.80) (Table ).. TABLE : Effect of different osmotic treatments on color of osmotically dehydrated slices of karonda at different stages of storage Initial Month of Storage Months of Storage 4 Months of Storage %NaCl %NaCl Control Concentration Duration(D) TxD

3 Volume 4, Issue, 05 4 TABLE : Effect of different osmotic treatments on texture of osmotically dehydrated slices of karonda at different stages of storage Initial Month of Storage Months of Storage 4 Months of Storage %NaCl %NaCl Control Concentration Duration (D) TxD TABLE : Effect of different osmotic treatments on flavour of osmotically dehydrated slices of karonda at different stages of storage Initial Month of Storage Months of Storage 4 Months of Storage %NaCl %NaCl Control Concentration Duration(D) TxD At two months of storage: There was a significant difference between s and duration of dipping times. Significantly highest score for colour (5.80) was observed in T 6 followed by T 5, whereas, lowest score (4.55) was observed in control sample (T 7 ).Among the osmotic pretreatments, significantly highest score (6.8) for texture was observed in treatment T 6. In osmotically treated samples scores for texture ranged from 0.55 to 6.8. In contrast, the lowest score (.55) was observed in untreated control slices. Effect of different osmotic treatments indicates that significantly highest score (7.45) for flavour was observed in treatment T 6 and ranged from.0 to Minimum score (.0) was observed in T for flavour and in control it was.0.highest total sensory score (79.4) was observed in treatment T 6 which was significantly superior from rest of the treatments and followed by T 5. While lowest total score (60.0) was noticed in T samples and in control it was 4.0. At 4 months of storage: The various osmotic pretreatments significantly affected the sensory score for colour and it was highest (.40) in treatment T 6 while the minimum value (6.5) for T and.55 value obtained for control sample (T 7 ). In osmotically dehydrated samples score varied from 6.5 to.40 which was in acceptable to highly acceptable range.the different treatments significantly affected the texture of dehydrated slices. In osmotically dehydrated samples score for texture ranged from 7.45 to The highest score (4.50) was observed in T and minimum score (0.58) was observed in case of control slices (T 7 ). The samples obtained from treatment T 6 were found significantly superior with respect to score for flavour (5.0) and followed by T 5. Score for flavour ranged from 9.0 to 5.0 in osmotically treated samples, while significantly lowest score (.0) was observed in untreated control (T 7 ) sample. Statistically significant variations due to different NaCl concentrations and dipping times were observed with respect to score for overall acceptability. Effect of different osmotic treatments indicates that karonda slices made using 5%NaCl for (T 6 ) rated significantly superior (7.0) and followed by T 5 (5%NaCl for ) The minimum score was observed in control (4.4) (Table 4). There was a significant differences between the treatments for taste, color, flavor, texture. Osmotically dehydrated slices showed better color initially than the two and four months. The gradual decrease in color, texture, flavour and over all acceptability of osmo-dried karonda slices during storage was observed. For texture, there was a significant difference only between the samples osmotically pretreated. Islam and Flink (98) reported that differences in texture may arise from differences in rate and extent of drying, together with the effect of infused solute. The osmotic dehydration before

4 44 ASIAN JOURNAL OF DAIRY AND FOOD RESEARCH drying has a protective effect on the structure of the dried material, which is characterised by a flexible and fluffy structure. The samples treated with tri sodium citrate (salts) retained the original color with more suitable flavor and texture when compared to non treated samples reported by Kaymak-Ertekin and Cakaloz, (996).The molecular weight of NaCl is small, the smaller molecular weight of solutes were penetrated into food more rapidly than higher molecular weight. The smaller molecular weight was desirable for the process of infusion then end product quality was excellent reported by Saurel et al.(994) and Kuntz, (995). Microbial count: There was no significant differences were observed in the s and duration of dipping times. The interaction between and duration of dipping was found to be significantly no difference. The lowest microbial colonies were observed in 5% NaCl and at of dipping of time (Table 5). At initial months of storage, the microbial count of the osmotic dehydrated karonda of various NaCl concentrations was nil initially and increased slightly duri ng stora ge. No microorganism was traceable initially due to the higher dilution used for the enumeration. There is no significant difference between s and duration of dipping.at two months of storage, Among the interactions, significantly highest microbial colonies (.00) was observed in T. In contrast, samples subjected to 5%NaCl for showed lowest colonies (0.66), while maximum colonies observed in control T 7 (4.00).At four months of storage, among treatments, significantly highest microbial colonies (5.00) were observed in T. In contrast, samples subjected to 5%NaCl for (T 6 ) showed lowest colonies (.00), while maximum colonies observed in control T 7 (7.66). In general the increased moisture content and acidity responsible for multiplication of microbes. Salt creates the alkaline condition around the product that arrest the microbial growth.increased microbial load was observed in all the treatments with the advancement of storage period at room temperature. In the osmotically dehydrated karonda slices it was found that an increase in concentration of salt as well as duration of osmosis resulted in low microbial count and preservatives like KMS, sodium benzoate and citric acid restricted the microbial growth. Basically salt act as a preservative for fruits and preservatives like KMS, sodium benzoate and citric acid reduced the microbial count during storage period. TABLE 4: Effect of different osmotic treatments on over all acceptebility of osmotically dehydrated slices of karonda at different stages of storage Initial Month of Storage Months of Storage 4 Months of Storage %NaCl %NaCl Control Concentration Duration(D) TxD TABLE 5: Effect of different osmotic treatments on microbial count in osmotically dehydrated slices of karonda at different stage of storage Initial Month of Storage Months of Storage 4 Months of Storage %NaCl %NaCl Control Concentration - NS Duration(D) - NS TxD - NS

5 Microbial quality of dried karonda slices depicted in indicated that the drying process substantially helped in reducing the microbial count of slices by reducing the water activity results in providing safety for consumption and enhancing shelf life of the product. Jorge and Favetto (99) also reported lower microbial load after drying due to reduction in water activity. The same results also observed in Keasr mango reported by Sakhale and Pawar (0). Volume 4, Issue, CONCLUSION Osmotically dehydrated slices showed better color, flavour, texture and over all acceptebility at initial stage than two and four months after storage under ambient conditions. However products was found acceptable. Overall acceptability was rated good (8.05) for osmotically dehydrated karonda slices produced through treatment T (5% NaCl for ) in case of NaCl treatments in terms of color, texture and flavour and with low microbial count. REFERENCES Alakal,i J.S.; Ariahu, C.C and Nakpa N.N (006). Kinetics of osmotic dehydration of mango. Journal of Food Processing and Preservation. 0: Fito, P.; Chiralt, A.; Barat, J.; Salvatori, D.; Andres, A.; Martinez-Monzo and Martinez- Navarrete, N. (00). Vacuum impregnation for development of new products. Journal of Food Engineering.49: Islam, M.N and Flink, L.N. (98). Dehydration of potato II osmotic concentration and its effect on air drying behavior. Journal of Food Technology. 7: Jorge, C and Favetto, G.J. (99).Some physico-chemical basis offood preservation by combined methods. Food Research International. 5: Kaymak-Ertekin, F and Cakaloz, T. (996). Osmotic dehydration of peas: Influence of osmosis on drying behavior and product quality. Journal of Food Processing and Preservation. 0: Kuntz, L.A.(995). Investigating Infusion. Food Product Design. Accessed 00 Aug l. Malik, S.K.; Chaudhury, R.; Dhariwal. O.P and Bhandari, D.C. (00). Genetic resources of tropical underutilized fruits in India. NBPGR, New Delhi Sakhale, B.K. and Pawar, V.N. (0). Studies on Effect of Syrup Concentration and Drying Modes on Quality of Kesar Mango Slices. Journal of Food Science and Engineering.: Saurel, R.; Raoult-Wack, A.; Rios, G and Guilbert, S. (994). Mass transfer phenomena during osmotic dehydration of apple. Fresh plant tissue. International Journal of Food Science and Technology. 9: Sharma, S.K. and Banyal, S.K. (00). Rehabilitation of marginal lands through karonda cultivation. Intensive Agriculture. Oct-Dec: 6-.