Defense Food Research Laboratory, Mysore-570 011, India
Received date: July 12, 2013; Accepted date: October 24, 2013; Published date: November 02, 2013
Citation: Lakshmana JH, Jayaprahash C, Kumar R, Kumaraswamy MR, Kathiravan T, et al. (2013) Development and Evaluation of Shelf Stable Retort Pouch Processed Ready-to-Eat Tender Jackfruit (Artocarpus heterophyllus) Curry. J Food Process Technol 4:274. doi:10.4172/2157-7110.1000274
Copyright: © 2013 Lakshmana JH, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Ready to Eat (RTE) tender Jackfruit curry was prepared and processed by using steam air retort with an overriding pressure of 15 lbs. The cumulative lethality value was 6.0 with a total processing time of 45 minutes. The tender jack fruit curry was stored under ambient (27 - 30°C). The samples were analyzed for changes in moisture, fat, free fatty acids, peroxide value, microbiological and texture, sensory quality attributes. The hardness of the tender jack fruit was reduced from 39 N to 9 N at blanching and 1 N at retort processed product due to heat induced softening of tissue. Further no significant changes were observed in free fatty acids and peroxide value during storage. The product was acceptable and stable up to 12 months under ambient condition with good texture and sensory characteristics.
Ready to Eat (RTE); Tender Jackfruit curry; Retort processing; F0 value; Free fatty acid
The tender jackfruits are highly nutritional, seasonal and highly susceptible for spoilage. The development and evaluation of tender jack fruit curry is aimed at value addition and product diversification which will result in improve the economy of farmers. This study will help the food industry to preserve and produce traditional value added product from tender jack fruit with extended shelf stability.
Jackfruit (Artocarpus heterophyllus) is a species of tree of the mulberry family (Moraceae) and its fruit, native to southwestern India. Jackfruit is commonly used in South and Southeast Asian cuisines . In general, the fresh deseeded sweet bulbs are consumed as such by the people and the bulbs cannot keep it for long time because of high perishability and as a result there are huge post harvest losses (30-35%) occurring during the season and also the usefulness of the seeds and rind is not known to the growers and consumers. Tender jackfruit has a mild pleasant flavor and distinctive texture, rich vitamins and minerals, plus isoflavones, phytonutrients and anti-oxidants . Tender jackfruit curry is exotically delicious and makes for a fantastic vegetarian dish, similar to chicken in consistency, and is even referred to as “vegetable meat” in many parts of Southeast-Asia. The tender fruits are seasonal, highly susceptible for spoilage.
Thermal processing of foods is one of the most important preservation techniques in the food industry to extend the shelf-life of foods. It generally involves heating of foods for a predetermined time at a preselected temperature to eliminate pathogenic microorganisms that endanger the public health as well as those microorganisms and enzymes that deteriorate the food during storage. Today, the consumer demands more than the production of safe and shelf-stable foods and insists on high-quality foods. The more severe the thermal process, the greater will be the degradation of food quality, both in sensorial (color, flavor, texture) and nutritional factors .
There is an increasing consumer demand for high quality convenient ready-to-eat food products and has led to an increase in the commercial production of ready-to-eat products [4,5]. This special category of food has been defined as a catering system on the partial cooking of food followed by thermal processing under elevated temperature, storage in ambient condition and subsequent thorough re-heating before consumption. Such foods covers a wide range of items include vegetarian and non-vegetarian foods. Retort (thermal) processing is intended to kill micro organism in food products to extend the shelf stability of the product, by the application of extreme heat condition (121.1°C). However, exposure of food to that condition may result in loss of nutritional and sensory qualities . Thermal process design is adopted to maximize microbial inactivation with minimal collateral degradation to product quality .
Retort processing has evolved significantly since its incorporation into Dept. of Defence (DoD) and NASA food systems. While the technology still relies on aggressive application and penetration of heat throughout foods, recent advancements in process engineering coupled with evolution of packaging technologies have allowed for an overall improvement of the technology [8-10]. The current state of the art in retort pouch processing has increased commercial value, and can offer to consumers a level of quality, safety, and convenience not realized by other means . Retort pouch processing technology has been widely familiar as one of the alternatives to metal cans for producing thermally processed shelf stable foods . The retortable pouch is a flexible laminated pouch that can withstand thermal processing temperatures and combine the advantages of the metal can and plastic packages. Flexible retortable pouches are a unique alternative packaging method for sterile shelf stable products . The retort pouch has many advantages over canned and frozen food packages for both the customers as well as food manufactures. The advantages are pouch profile, storage and preparation efficiency, savings in transportation, package cost, improved flavor and savings of energy . The main aim of the present study was development and evaluation of develop Retort pouch processed Ready-to-eat Tender Jackfruit (Artocarpus heterophyllus) curry and changes in chemical, textural, microbial and sensory characteristics during storage.
Tender Jack fruit curry (heterogeneous vegetarian product containing jack fruit, cow pea, onion, garlic, ginger, spices and hydrogenated fat). The cow peas and jackfruit was blanched in boiling water bath for 10 minutes. The following flow chart (Figure 1) describes the jackfruit curry preparation and retort processing.
Pre-fabricated multilayer laminated retortable pouches consisting of 12 mm Polyester/12 mm Aluminium foil/75 mm Cast-Polypropylene (PET/ Aluminium foil / C.PP) of dimension 15 cm × 20 cm were used to fill the product.
Filling and sealing
The 200 g of the product was filled manually and then, entrapped air in the head space was manually squeezed out before sealing the top of the pouch hermetically by an impulse heat sealer (Model: HP Impulse Sealer, M/S Sunray Industries Mysore, India). The filled and sealed pouches were loaded into Retort vessel.
Retort pouch processing of Jack fruit curry
Retort pouch processing of Tender Jack fruit curry was carried out in a steam-air retort (M/s. Alpha Steritech, Bangalore, India). The retort was equipped with facility for using compressed air for over-riding pressure and a high-pressure water-circulating pump for pressurized cooling. The temperature of the product was continuously recorded during heat processing, through copper-constantan thermo couples, which were fixed at the geometric centres of the pouches and connected to a data logger (Model: E. Val flex, M/s. Ellab, Denmark).The pouches were placed at different locations in the retort. The temperature of the pouch and retort was calculated from the thermo-electro-motiveforce at regular intervals of 1 min. The F0 value was calculated from the temperature and time history. The pouches were initially heated till there inside temperature reached 121°C. Subsequently, the pressure of the steam was raised in stages; from 5 lbs to 15 lbs. gauge pressure with the increase of temperature progressively. The processing was carried out to achieve a F18250 value value of 2.0  with maximum temperature of 118°C. After attaining the required F0 value, the product temperature was brought down to 50-55°C by pressurized cooling (compressed air and water) in 4-5 minutes. The cooled pouches were wiped dry and examined for any visual defects.
The Retort processed Tender Jack fruit curry was analysed for their commercial sterility. The pouches were incubated at 37°C and 55°C for 7 days. SPC was determined using dextrose tryptone agar (DTA) after incubation for 48 h at 30°C. Yeast and moulds were estimated with the help of acidified potato dextrose agar (PDA), after incubation at 30°C for 4-5 days. Streaking the enriched sample with selentine cystine broth at 37°C for 24 h, 48 h and 72 h were tested for salmonella and shigella. Spore formers were determined after killing the vegetative cells by keeping the sample in boiling water bath for 10 to 20 minutes and subsequently incubated at 37°C and 55°C for 48 h after incubation . The samples were analysed with three determinations.
The processed Tender Jack fruit curry was stored under ambient (27-30°C). The proximate composition  (carbohydrates was calculated by difference) and the microbial quality, free fatty acid (FFA) and Peroxide value (PV) of samples were analysed at an interval of 2 months for acceptability and safety of the product. The samples were analysed with three determinations.
The Retort processed Tender Jack fruit curry was evaluated for quality and acceptability on a 9-point hedonic scale by semi- trained panel with score 9 for samples Like extremely in all respects, while 1 for extremely dislike ones. The samples were analysed with ten determinations.
Texture profile of Raw, blanched and retort processed Jack fruit were analysed using Universal testing machine with 1KN load cell (Model: Lloyd Instrument, Made in UK) to find out its hardness. The hardness was measured by cutting the slices (2.5 × 2.0 cm). The samples were analysed with five determinations.
The data were analysed statistically to find out standard deviations and significance .
Physico-mechanical and barrier properties of multi layer retort pouch
The effect of retort processing on physico-mechanical and barrier properties of multi layer retort pouch is given in Table 1. There is a significant reduction in tensile, tear, % elongation and seal strength after retort processing. Our results accordance with other authors , the reduction in these properties may be due to heat induced changes in the polymer matrix. Further, there were no significant changes in gas and water vapour transmission rates before and after processing. This is mainly due to the presence aluminium foil as barrier layer. After retort processing the overall migration level in packaging material was well within the prescribed limits of FDA .
|Parameters||Before retort processing||After retort processing|
|12 µm Polyethylene terephthalate (PET) / 9 µm Aluminium foil / 15 µm Nylon / 70 µm Cast Polypropylene|
|Total thickness μm||110||110|
|Tensile strength (Machine Direction) kg / cm2||446.58||437.49|
|Tensile strength (Cross Direction) kg / cm2||358||349|
|Elongation at break (Machine Direction)%||156||149|
|Elongation at break (Cross Direction) %||124||112|
|Tearing strength (Machine Direction) g||116||108|
|Tearing strength( Cross Direction) g||102||96.0|
|Seal strength (Top) kg /10mm||3.96||3.78|
|Seal strength (Side) kg/ 10mm||4.86||4.26|
|Seal strength (bottom) kg / 10 mm||4.02||3.86|
|Gas transmission rate (ml/m2/day)||<0.021||<0.038|
|Water vapour rate (gm/m2/day)||<0.019||<0.032|
|Total migration ( mg / kg)|
|3 % Acetic acid||38.0||42.0|
|50 % Ethyl alcohol||26.0||29.0|
Table 1: Physico-mechanical and barrier properties of multi layer laminate retort pouch.
The product was prepared as per the recipe standardized by this laboratory and retort processed as prescribed by Code of Federal Regulations. The come up time for the product to reach 121°C was 10- 12 min. After attaining 121°C the product was subjected to steam-air mixture (15Psi + 5Psi) and the product temperature reach to 118°C in 15 min. The lethality of the product was achieved the desired F0 value 6.8 and 6.7 for probe 1 and probe 2 respectively. Then it was brought to 50-55°C by pressurized water-cooling. The time-temperature and lethality history curve of the product is shown in Figure 2. The product F0 value was achieved more than desired value of it.
The total plate count, yeast and mould count, coliforms count and spores count were found to be 2.4 × 102, 0.5 × 101, nil, < 101 respectively. The microbiological analysis of jack fruit curry showed that the product remained commercially sterile during the entire period of the ambient (27-30°C) storage and confirmed the adequacy of the processing as well as its fitness for consumption. Similar results were obtained by other authors [13,14] and they also found commercially sterility after processing and the entire period of the storage.
The proximate analysis of Retort processed jack fruit curry was presented in Table 2. The product was analyzed for its initial moisture, total fat, protein, fiber, ash and carbohydrates and the values were 77.98 ± 0.5, 3.30 ± 0.42, 3.11 ± 0.120, 2.30 ± 0.500, 1.68 ± 0.100 and 12.03 ± 0.00 respectively. No significant change in the moisture content of the product was observed during storage. The packaging system based on aluminium foil has been already reported by other author  providing excellent barrier against mass transfer, gas, light and microorganisms. While the fat content of the product was found to be reduced during storage where as no significant changes in protein content observed till the end of 12 months storage. Similarly, no significant changes noticed in fiber, ash and carbohydrates content during storage under ambient condition. Our result accordance with other author  who studied the ready to eat retort pouch processed coconut kheer and observed similar results during storage.
|Storage (months)||Moisture (%)||Total Fat (%)||Protein (%)||Fibre (%)||Ash (%)||Carbohydrate (%)|
|0||77.98 ± 0.05||3.30 ± 0.42||3.11 ± 0.120||2.30 ± 0.500||1.68 ± 0.100||12.03 ± 0.00|
|2||77.90 ± 0.50||3.25 ± 0.47||3.12 ± 0.470||2.34 ± 0.001||1.66 ± 0.050||11.73 ± 0.00|
|4||77.80 ± 0.30||3.21 ± 0.46||3.10 ± 0.420||2.35 ± 0.010||1.67 ± 0.040||12.07 ± 0.00|
|6||78.01 ± 0.50||3.20 ± 0.28||3.21 ± 0.500||2.31 ± 0.050||1.68 ± 0.100||11.72 ± 0.00|
|8||77.90 ± 0.40||3.09 ± 0.24||3.20 ± 0.005||2.25 ± 0.040||1.66 ± 0.040||11.90 ± 0.00|
|10||78.20 ± 0.50||3.09 ± 0.24||3.23 ± 0.010||2.28 ± 0.050||1.70 ± 0.500||11.39 ± 0.00|
|12||78.00 ± 0.50||3.07 ± 0.50||3.24 ± 0.020||2.32 ± 0.001||1.69 ± 0.001||11.54 ± 0.00|
Mean ± SD of three determinations
Table 2: Proximate composition of Retort pouch processed RTE tender jackfruit curry at ambient (27-30°C) temperature storage.
Free Fatty acid (FFA) and Peroxide Value (PV) analysis
The initial free fatty acid content (% of oleic acid) and Peroxide Value of tender jack fruit curry (m.eq. of O2/kg fat) were found to be 0.29 ± 0.06 and 5 ± 0.12 respectively. The sample was stored under ambient (27-30°C) condition and analyzed at an interval of 2 months to found out the development of rancidity. The changes in free fatty acid and peroxide value of jack fruit curry during storage were given in Figures 3 and 4. Hence no significant development of rancidity and off flavor observed during storage. The increase in FFA and PV were gradual and linear during storage. However no significant development of off flavor of the product was noticed. This is mainly because of the presence layer of an aluminium foil (12 mm Aluminium foil) which has been reported to provide excellent barrier against mass transfer, gas, light and microorganisms. Our results were compromise with other authors [20-22] they also reported that, the gradual increase in the FFA content of retort pouch processed products during storage.
The Sensory quality of analysis of jackfruit curry using a 9-point hedonic scale score revealed that initially the product scored 8.3 ± 0.42 for color, 7.9 ± 0.47 for flavor, 8.1 ± 0.52 for taste, 8.0 ± 0.86 for texture and 8.1 ± 0.87 for Overall acceptability (Table 3). On storage, the sensory scores was decreased significantly and also with in acceptability limit. Under ambient (27-30°C) conditions the sensory scores decreased to 7.4 ± 0.52 for color, 6.9 ± 0.57 for flavor, 7.4 ± 0.70 for taste, 7.1 ± 0.70 for texture and 7.2 ± 0.71 for overall acceptability Overall acceptability and thus clearly indicating the effect of storage conditions on the quality attributes of the product. However, the samples stored at ambient (27-30°C) were acceptable up to 12 months of storage as the Overall acceptability score of the product remained in good.
|0||8.3 ± 0.42||7.9 ± 0.47||8.1 ± 0.52||8.0 ± 0.86||8.1 ± 0.87|
|2||8.3 ± 0.74||7.9 ± 0.47||8.1 ± 0.92||8.0 ± 0.47||8.1 ± 0.92|
|4||8.2 ± 0.74||7.9 ± 0.47||8.0 ± 0.92||7.9 ± 0.47||8.0 ± 0.92|
|6||8.0 ± 0.92||7.8 ± 0.57||7.7 ± 0.83||7.5 ± 0.79||7.7 ± 0.86|
|8||7.8 ± 0.42||7.4 ± 0.70||7.5 ± 0.71||7.9 ± 0.47||7.6 ± 0.52|
|10||7.6 ± 0.52||7.1 ± 0.57||7.3 ± 0.70||7.5 ± 0.70||7.3 ± 0.71|
|12||7.4 ± 0.52||6.9 ± 0.57||7.4 ± 0.70||7.1 ± 0.70||7.2 ± 0.71|
Mean ± SD of ten determinations
Table 3: Sensory Evaluation of Retort pouch processed RTE tender jackfruit curry at ambient (27-30°C) temperature storage (*9 point Hedonic Scale).
Textural Profile Analysis (TPA)
Texture Profile Analysis (TPA) of raw tender jack fruit, blanched and retort processed was carried out using Universal Testing Machine (UTM) equipped with TPA software and given in Table 4. The hardness of the tender jack fruit reduced significantly after retort processing from 39.78 ± 2.81 to 0.95 ± 0.19. Change in the hardness is affected mainly due to the heat induced thermal softening of tissues . Further, the changes in cohesiveness, springiness, gumminess and chewiness were significant in fresh, blanched and retort processed samples. However, the overall texture of retort processed tender jack fruit curry was acceptable. Similarly other authors also observed decreases change in hardness throughout the storage of retort processed paneer curry .
|Samples||Hardness (N)||Cohesiveness||Springiness (m)||Gumminess (N)||Chewiness (Nm)|
|Raw Tender jackfruit||39.78 ± 2.81||0.34 ± 0.03||0.015 ± 0.002||13.62 ± 1.18||0.2071 ± 0.0428|
|After Blanching||09.13 ± 1.36||0.25 ± 0.03||0.014 ± 0.002||02.36 ± 0.60||0.0343 ± 0.0067|
|After retort processing||00.95 ± 0.19||0.18 ± 0.13||0.006 ± 0.003||00.15 ± 0.08||0.0013 ± 0.0011|
Mean ± SD of Five Determinations
Table 4: Texture Profile Analysis (TPA) of Raw, Blanched and Retort processed tender Jackfruit curry.
A common variation is an existing line of new product developments to get health benefits, for example, a new flavor or texture, a new package style or size, a different content of a key ingredient (e.g. rich fiber, reduced fat or sugar). Thermal (retort) processing has the potential to produce high quality, shelf stable food products. The present study to development of shelf stable jack fruit curry give excellent mouth watering recipe with high fibre content, since it is low acid products shows thermal processing to target F0 value in achieving microbial commercial sterility and improved sensory characteristics in ready-to-eat Tender Jack fruit curry was established with 12 month shelf life.