Browsing by Author "Rajesh, G K"

Now showing 1 - 11 of 11

Development and evaluation of a continuous cacoa pod breaker
(Department of Food and Agricultural Process Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2016) Srikanth Vankayalapati; Rajesh, G K
Cocoa {Theobroma cacao) is a commercial plantation crop in India. It is the main raw material in the production of chocolates, cosmetics, health drinks, pharmaceuticals etc. The cocoa beans which are embedded in a mucilaginous pulp inside the pod consist of two parts- seed coat and seed cotyledon. Seed cotyledon is the material in which characteristic flavour and aroma produced during fermentation. At present, cocoa pod breaking and bean extraction from crust pod are done manually by using sickle which is a labour intensive method. Manual chopping could increase the number of damage bean which leads to fungal attack. In order to eliminate the drudgery involved in manual cocoa pod breaking, avoid injury to workers, increase efficiency and to ensure high quality products, an attempt was made to develop a continuous cocoa pod breaker. Before the fabrication of machine, the engineering properties of cocoa viz., physical, mechanical and frictional properties of fresh cocoa pod were determined. Physical properties studied were size, shape, mass and density. The mechanical and frictional properties viz., compression test, angle of repose and co-efficient of friction were determined as per the standard procedures. The continuous cocoa pod breaker consists of hopper, metal rollers, chute, rotating cylindrical strainers, frame, prime mover and pulleys. Cocoa fruit was fed manually in to breaker unit through hopper. Gap between the rollers was set so as the cocoa kernels were not damage during the pod breaking process. Tangential force of the roller pushed the cocoa pod towards the gap resulted in breakage. Cocoa pod, kernels and placenta then discharged to strainer through chute. Rotation of strainer separated the cocoa kernels from cocoa pod and placenta, and passed through the pores of the strainer. It was then collected and could be directly send for fermentation process. The broken pods were remained above the strainer and got separated. Performance of the machine was evaluated in terms of capacity, energy requirement, percent bean damage, per cent bean recovery, shelling efficiency and machine efficiency. The average capacity and breaking efficiency of cocoa pod breaker was 550.5 kg/h and 95-98 percent, respectively. Bean damage percentage was 0.5 per cent. The shelling efficiency and beans separation efficiency of the strainer at inclination, 45° 96.42 and 86.5 per cent, respectively. The performance of the developed cocoa pod breaker was compared with traditional method of pod breaking, the total time required to break 100 kg cocoa pods and collect the beans for mechanical and manual method was 10.44 and 50.17 minute, respectively. The field evaluation of the developed machine was done with two cocoa varieties viz., Criollo and Forastero. The performance of the machine was evaluated based on its capacity, per cent bean damage, efficiency of cocoa pod breaker and energy requirement. From the field trail it is understood that, the efficiency of the machine is higher for Criollo variety as compared to Forastero variety. The fermentation studies were conducted in artificial fermentation chamber, poly house and ambient condition and it was compared with three different environmental conditions (ambient, poly house and fermentation chamber). The effects of treatments on dependent variables like temperature, pH. moisture content and microorganisms during fermentation process were studied. In this study, fermentation of cocoa beans on all methods in the artificial fermentation chamber found the best among the other treatments for the production of good quality cocoa. Similarly, the box method was found the best among the other treatments for the production of good quality cocoa.The cost of operation of cocoa pod breaker of 550 kg/h capacity was estimated as Rs.74.42/-
Development and evaluation of process protocol for vacuum fried carrot chips (Daucus Carota L)
(Department of Processing and Food Engineering, KCAET, Tavanur, 2021) Babu, P; Rajesh, G K
Carrots are highly nutritious vegetable, which can be consumed in raw and processed form throughout the world. Carrot plays a vital role in the development and protection of human body. Carrot contains vitamins viz., B1(Thiamine), B2(Riboflavin), B6(Niacin) and B12 (Cobalamin) besides rich in source of βcarotene and dietary fibre which are helpful to prevent cancer and other dreadful diseases occur in human body. In Kerala state, carrot production is very limited, but its consumption is more. The postharvest losses of carrot were estimated as 18- 20%. The development of value-added products from carrot was an idealistic solution to reduce the postharvest losses by adopting new processing technologies. At present, due to consumer’s awareness, there is a lot of demand for healthy and tasty snack products with less oil content which provide good health. In this context, investigation on processing technologies focus on producing high quality fried products with less oil content and good textural property. The technology of vacuum frying is a best option for the production of novel snacks which fulfil the consumers demand and meet nutritious requirements. Vacuum frying is a novel technology, in which the food is heated under lower temperature and pressure(<6kPa). Vacuum frying lowers the water activity, oil content, retains the color and preserve nutrients in the fried product. The batch type vacuum frying system consists of two chambers viz., frying chamber (3kg capacity) and oil storage chamber (30-35L capacity). The refined palm oil was used for vacuum frying and de-oiling was done at 1000 rpm for 10 min. After every batch of vacuum frying, the oil was collected for quality analysis. Prior to the research, the physico-chemical properties of raw carrot (Ooty-1) was determined. The pre-treatments viz., blanching, blanching cum drying, blanching cum freezing, freezing and gum coating were optimized based on the quality of vacuum fried carrot chips. The freezing pre-treatment obtained the best results among other pre-treatments in terms of less oil content (14.48 %), water activity (0.214), moisture content (2.67%), hardness (1.282 N) and red color retention of a* value (22.85). The standardization of process parameters were done using RSM (CCRD) based on the quality characteristics of VF-carrot chips. The process parameters seected in this study were frying temperature (100,110 and 1200C), frying pressure (11,13 and 15 kPa) and frying time (16,18 and 20 min). The optimum operating conditions of vacuum frying viz., frying temperature, vacuum pressure and frying time were found to be 100°C, 11 kPa and 16 min respectively. At optimum operating conditions of 100°C, 11 kPa and 16 min, the quality parameters were oil content (11.31%), bulk density(0.873 g/cm3 ), true density(1.714 g/cm3 ), moisture content(3.28%), water activity (0.384), hardness (1.31 N),thickness expansion (60.42%), L*(43.48), a*( 14.36) b*(28.12) and energy content(1021 KJ/100g). Packaging and storage studies were conducted for the treatments which had high sensory score. The laminated aluminium flexible pouch with N2 gas filling was found to be the best packaging technique to enhance the shelf life of VF carrot chips to a storage period of 4 months. The oil quality parameters viz., total polar compounds (TPC), viscosity, peroxide, free fatty acids (FFA) etc were within the allowable limits even after 40 batches of vacuum frying. The total production cost of 1kg of vacuum fried carrot chips was found to be Rs. 355/-.
Development and evaluation of semi-continuous microwave convective dryer for food products
(Department of Processing and Food Engineering, Kelappaji College of Agricultural Engineering ,Tavanur, 2024-05-10) Alfiya, P V; Rajesh, G K
The research work aimed to develop a semi-continuous microwave convective dryer for foods and evaluate the performance of the dryer for drying of shrimp and oyster mushroom. The study also aimed to assess the shelf-life of the dried products under different packaging technologies and packaging materials. The quality of conventionally dried shrimp and oyster mushrooms were compared and evaluated with the hot air assisted microwave (HAMW) dried products. The developed HAMW drying system comprised of a drying chamber, conveyor belt, magnetron to generate microwaves at frequency of 2450 MHz±50 MHz, hot air generation system with air heater, axial fan and other controls. The drying experiments for shrimp were performed according to a second-order Box- Behnken design (BBD) with three factors at three levels: microwave power (600, 800 and 1000 W), air temperature (50, 60 and 70 °C), and air velocity (0.5, 1.0 and 1.5m/s). Drying time, water activity, and rehydration ratio was selected as the response variables. A three-factor, three-level Box-Behnken design (BBD) experimental design was used in optimizing the drying conditions for shrimp in a hot air-assisted microwave (HAMW) drying system. The optimization was performed to optimize the conditions with minimum values of drying time and water activity, and maximum value of rehydration ratio. The design plan consisted of 17 runs with 5 centre points. The optimum conditions of process variables were derived using the desirability function. Design Expert Statistical Software package 9.0.0 (Stat Ease Inc., Minneapolis, MN, USA) was used to perform statistical analysis. The moisture content of shrimp decreased from an initial value of 80.55% to a final value of 16.5% within 2.9 h of drying. HAMW drying of shrimp was represented by reduction in moisture percent as a function of drying time. Moisture ratio obtained during drying were fitted into thin layer drying models by non-linear regression analysis. Page model was identified as the best fit model with higher R2 value of 0.9984, lower χ2 value of 0.000134 and RMSE value of 0.01552. Drying efficiency of the dryer under HAMW mode was observed to be 35.71%. This was a result of volumetric hearing effect of microwave radiation combined with convective effect of hot air. The SEC value for HAMW of shrimp was found to be 1.75 kWh/kg. The total value of colour change (ΔE) determined for dried shrimp was 16.95 ± 2.14. The ‘L’ value of the dried shrimp (41.31 ± 1.63) decreased during drying whereas the ‘a’ and ‘b’ values increased from 3.56 ± 1.54 to 14.23± 2.36 and 12.42 ± 0.65 to 19.42 ± 1.61 during the drying process. 265 Solar radiation, ambient temperature and relative humidity (RH) were measured using sensors at each hour of the study. The solar radiation intensity during the experimental conditions was observed to be in range of 320 to 840 W/m2, ambient temperature varied from 27.5 to 36.5 0C and RH from 62.45% to 77.24% on a typical day of the experiment. The moisture content of shrimp was reduced from 80.2% to 15.7% (w.b.) within 6 h of drying in the solar dryer. The drying conditions were maintained at temperature, air velocity and RH of 55±1.5 0C, 1.5 ± 0.25 m/s and 60±0.5 % respectively. The drying rate of solar and microwave dried shrimp was found to be 1.63 kg/kgh and 2.74 kg/kgh at the beginning of drying. Drying rate exhibited a maximum value of 2.74 during The average rehydration ratio was observed to be 2.39 and 2.53 for SD and HAMW drying respectively. The shrinkage percentage of SD and HAMW shrimp was observed to be 24.67 and 14.14% respectively. Storage studies of hot air assisted microwave dried and solar dried shrimps were carried out under MAP and vacuum conditions in three types of packaging materials namely LDPE (150 μ), polyester polyethylene laminate (72 μ) and metallised polyester (84 μ). Shelf life of the dried shrimps was quantified with respect to the microbial growth and other quality parameters. Maximum storage life was exhibited for SD and HAMW dried shrimp under polyethylene-polyester laminated (72 μ) packaging material. The response surface methodology plots of Oyster mushrooms showed that drying time decreased with an increase in air temperature (40 to 60℃) and microwave power (600 to 1000W). Based on the value of maximum desirability (0 to 1), optimum conditions were selected. The methodology of desired function was applied to indicate 55.05 ℃ air temperature, 1000 W microwave power and 0.81 m/s air velocity which indicated the drying time, water activity and rehydration ratio of 5.05 h and 0.532 and 2.49, respectively with a desirability value of 0.830. Moisture content of Oyster mushroom decreased from 92.35 to 8.42% within 5 h of drying. Volumetric heating effect of microwaves can be attributed for the reduction in drying time. Microwave heating falls under dielectric heating method wherein the moisture content of the product directly influences the heating rate. Drying rate exhibited maximum value of 3.47 during the initial stages in drying that can be due to the higher moisture content of sample that created more friction and heat generation due to dipole rotation. Drying efficiency of the dryer under HAMW mode for oyster mushroom was observed to be 23.12%. The SEC value for HAMW of oyster mushroom was found to be 2.71 kWh/kg. Solar drying efficiency of the collector was calculated using the whole collector area 266 and solar irradiation received instantaneously during drying. The instantaneous collector efficiency values varied in the range of 30.9 to 42.4%. The L*, a* and b* colour values of fresh mushrooms were determined to be 84.12±0.46, 3.3±0.24 and 15.57±0.62 respectively. The colour values of the microwave dried mushrooms under optimized conditions were recorded as 56.15±0.25 (L*), 4.95±0.24 (a*) and 20.85±0.51 (b*) respectively. The ‘L’ value of the dried oyster mushroom decreased whereas the ‘a’ and ‘b’ values increased during microwave convective drying. The drying rate of SD and HAMW dried oyster mushrooms were found to be 3.47 kg/kgh and 2.14 kg/kgh at the beginning of drying. Drying rate exhibited a maximum value of 3.47 during the initial stages of drying that can be due to the higher moisture content of a sample that created more friction and heat generation due to dipole rotation. Drying reduced the TPC value of oyster mushroom to 1.2 × 104 and 3.9 ×105 CFU/g respectively under MW and SD drying conditions. The optimized sample was analysed for microstructure to study the pore size distribution in the dried product. The pore size for microwave dried oyster mushroom samples ranged from 8.65 – 32.4 μm. Scanning electron microscopy analysis of microwave dried oyster mushroom showed the formation of pores of diameters ranging from 2.06 – 15.7 μm. Storage studies of hot air assisted microwave dried and solar dried oyster mushrooms were carried out under MAP and vacuum conditions in three types of packaging materials namely LDPE (150 μ), polyester polyethylene laminate (72 μ) and metallised polyester (84 μ). Shelf life of the dried oyster mushroom was quantified with respect to the microbial growth and other quality parameters and maximum value of 9 months was achieved for SD and HAMW dried oyster mushroom in polyethylene-polyester (72 μ) laminated packaging Material.
Development and quality evaluation of spray dried probiotic flavoured yoghurt containing
(Department of Food and Agricultural Process Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2017) Sreekutty Suresh, V; Rajesh, G K
Development and quality evaluation of thermally processed cassava in retort pouch
(Department of Processing and Food Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2018) Rasmi Janardhanan; Rajesh, G K
Cassava (Manihot esculenta Crantz), popularly known in India as tapioca, is one of the important food crops providing livelihoods and food security for millions of people in the tropical regions. High moisture content of cassava, leads to early deterioration due to microbial attack and also makes it susceptible to desiccation and mechanical injury. Therefore effort has to be put in so that cassava is made available to all the people year-round either in raw, preserved or processed manner. Therefore, an investigation has been taken up to develop and optmise a process protocol, which could contribute to cassava based industries. The study was conducted on two varieties of cassava namely, Sree Jaya and M-4. The physicochemical analysis of both the varieties were conducted and recorded. The blanching time at 100 ̊C was optimized and quality improvement with addition of 0.1 per cent guar gum was conducted. The blanching time for M-4 was optimised as 5 minutes in 0.1 per cent guar gum and for Sree Jaya the blanching time was optmised as 15 minutes in 0.1 per cent guar gum. Calcium chloride brine with 0.4 per cent concentration was selected as the filler solution. Thermal processing was conducted at 100, 110, 121 ̊C with different time combinations. The retort pouch processing parameters were optimised and the shelf life studies of the microbiologically safe samples were conducted for six months at refrigerated condition and three months at ambient conditions. From the storage studies and the sensory analysis it was concluded that Sree Jaya thermally processed at 110 ̊C for 20 minutes with F0 2.1 and M-4 thermally processed at 110 ̊C for 40 minutes with F0 6.1 are the best thermal processing treatments. The quality parameters and the sensory attributes of the processed cassava were best throughout the storage period. The cost of one pouch of 100 g was estimated to be Rs.19.20/- only. The optimised treatment resulted in a product which resembled the fresh sample, available to the consumers in a ready to eat form throughout the year.
Development of a chocolate enrobing machine for cookies
(Department of Processing and Food Engineering, Kelappaji College of Agricultural Engineering and Food Technology, Tavanur, 2025-02-23) Haritha, V; Rajesh, G K
Chocolate coating is usually applied using a chocolate enrobing machine. This is a machine in which the products to be coated pass through a continuous curtain of chocolate. Due to immense demand of cocoa value added products, several Self Help Groups (SHGs)/ home made units have started several enterprises in cocoa processing. However, a small capacity enrobing machines suitable for small and medium scale entrepreneurs are not available. Hence, an attempt has been made to develop economically feasible chocolate enrobing machine for cookies that will be suitable for small and medium scale entrepreneurs and beneficial to SHGs. Physico-chemical and engineering properties of cookies and compound milk chocolate were determined prior to the development of machine. The machine was designed and fabricated by considering critical parameters related to both cookies and chocolate. The developed chocolate enrobing machine consists of chocolate tank with agitator, water tank with heater, conveyor belt, chocolate flow pan, air flow duct connected with ring blower, vibrator, collecting tank and control panel. To optimize the process parameters for the enrobing process, Box-Behnken design was selected for the experimental design with 3 levels of independent variables viz. flow rate of chocolate (3, 4.5 and 6 kg/min), belt speed (2.1, 2.3 and 2.5 m/min) and flow rate of hot air (3.3, 3.6 and 3.9 L/s). The optimization of process parameters was done based on the responses viz. capacity, enrobing efficiency, energy requirement and coating thickness. The optimal conditions for the chocolate enrobing process were chocolate flow rate of 4.5 kg/min, belt speed of 2.5 m/min and hot air flow rate of 3.3 L/s. Performance evaluation of machine was done under optimized condition in terms of capacity, enrobing efficiency and energy consumption. The machine achieved a capacity of 190 cookies/hour, enrobing efficiency of 94.74%, energy consumption of 5.48 kWh and coating thickness of 2.79 mm. The quality attributes of optimized chocolate enrobed cookies were evaluated in terms of thickness, diameter, water activity and proximate analysis. The energy value of chocolate enrobed cookies was higher than that of base cookies. Sensory evaluation revealed that the optimized enrobed cookies was superior in terms of colour, appearance and overall acceptability among the other samples. The benefit-cost ratio and payback period were calculated as 1.05:1 and 3.15 years, respectively. It is concluded that the developed chocolate enrobing machine marks a significant step towards supporting small and marginal cocoa growers and entrepreneurs. It not only boosts the economic potential of cocoa growers, but also encourages new entrepreneurial ventures in rural as well as semi urban areas.
Develpment and evaluation of protein enriched RTE extruded food products
(Department of Processing and Food Engineering, KCAET, Tavanur, 2019) Athira, K; Rajesh, G K
Microencapsulation of ultrasound extracted jamun juice by spray drying
(Department of Processing and Food Engineering, Kelappaji College of Agricultural Engineering and Food Technology, Tavanur, 2025) Sankar, M.; Rajesh, G K
Jamun (Syzygium cuminii) is an under-utilized fruit tree from Indian subcontinent. The promising values of phytochemicals, minerals and vitamins gives a great therapeutic value for jamun. Jamun is a seasonal fruit. To reduce its post-harvest losses, various value-added products can be produced from jamun's pulp, juice, and seeds. Processing and preservation techniques must be adopted to ensure the availability of jamun throughout the year. Common unit operations to be performed in jamun processing include juice extraction and drying. Though jamun contains 80% pulp, conventional extraction methods yield relatively low juice. Therefore, an improved extraction method is essential to enhance both yield and nutritional quality. Ultrasound, a promising "green technology," offers an efficient alternative for juice extraction, while spray drying is one of the best drying techniques for liquid foods. The process parameters for ultrasound-assisted extraction of jamun juice were optimized based on the quality attributes of the extracted juice. Three levels of US treatment temperature (10,20,30°C), exposure time (30,60,90 mins) were selected for extraction study. A solid - liquid ratio of 2:1 was fixed based on the preliminary trials of extraction. The response variables selected were pH, TSS, acidity, total phenolic content, total anthocyanin content, antioxidant activity and yield, respectively. Central composite design was framed for the experimental design. Optimization of process variables for extraction process was done based on the quality attributes of the extracted jamun juice. The optimized process variables for juice extraction were determined to be a treatment temperature of 30°C, an extraction time of 60 minutes and a solid-to-liquid ratio of 2:1. For spray drying, Box- Behnken design was selected as the experimental design with three process variables of inlet air temperature (140,150,160°C), feed rate (8,10,12 rpm) and carrier concentration of (15,20,25%). From the preliminary trials conducted, maltodextrin and gum arabic, used as carrier materials, were found to be most effective for spray drying jamun fruit juice when combined in a 3:1 ratio. The response variables selected for spray drying were powder yield, moisture content, water activity, bulk density, tapped bulk density, wettability, dispersibility, solubility, total anthocyanin content and total colour difference. The process optimization for ultrasound extracted, spray dried jamun juice powder identified the optimal variables as an inlet air temperature of 160°C, a feed rate of 10 rpm, and a carrier concentration of 21%. The optimized sample contained a powder yield of 65%, moisture content of 3.9% water activity of 0.29, bulk density of 0.29 g/cm³, tapped bulk density of 0.43 g/cm³, wettability of 71 seconds, dispersibility of 92%, solubility of 96%, total anthocyanin content of 690 mg/100 mg, and a total colour difference of 46, respectively. The SEM images showed that the ultrasound treated powder contained smaller sized particles compared to the untreated powder. FTIR analysis confirms that the optimized powder contains important phenolic groups, as indicated by the presence of various bonds in the spectrum. The encapsulation efficiency of the anthocyanins was achieved as 96%. The proximate composition of the optimized spray-dried jamun juice powder was found to be 354.76 kcal of energy, 81.1% carbohydrate, 4.9% protein, 1.5% total fat, 24.56% total sugar, 1.2% total ash, and 0.3% fibre, respectively. Sensory evaluation showed that the optimized powder sample had high acceptability with a satisfactory score of 7.85. After 90 days of storage, samples stored under metalized polyester pouches provided good results based on quality parameters. The benefit-cost ratio of the US extracted jamun juice powder spray drying was found to be 1.1:1 with payback period of 2.84 years.
Optimization of spray drying parameters for passion fruit juice
(Department o Processing and Food Engineering, Kellappaji College of Agricultural Engineering and Technology,Tavanur, 2022-04-29) Fathima, K S; Rajesh, G K; Anu Varghese
Passion fruit (Passiflora edulis v. flavicarpa) juice attracts consumer attention due to its unique flavor and aroma. The passion fruit juice has so many health benefits due to the presence of vitamins (riboflavin, vitamin C, vitamin A and niacin) minerals (potassium, calcium, phosphorous, and magnesium) and antioxidants (vitamin C, betacarotene, and polyphenols). Kerala has all sets of climate and sufficient rain fall for cultivating passion fruit. The conventional preservation techniques viz. freezing and concentration was not adequate. Since passion fruit is highly perishable in nature, cold chain is essential to extend its shelf life. The poor processing and transportation facility in Kerala state hinders the cold chain. In this context, spray drying was found to be promising technology to preserve passion fruit juice for longer period at ambient temperature. Hence the aim of the study was to develop spray dried passion fruit juice powder. Maltodextrin and corn starch at 3:2 ratios was chosen as wall material. Passion fruit juice mixed with wall material at 15 %, 17.5 %, and 20 % w/v to prepare feed solution. For spray drying, the inlet air temperature set as (150 °C, 160 °C and 170 °C) and feed rate set as (8, 10, and 12 rpm). The Box- Behnken design of RSM (Design Expert software- Version 7.0. 0) was applied to optimize process parameters viz., wall material concentration, inlet air temperature and feed rate based on physico-chemical properties of the spray dried passion fruit juice powder. The optimized process conditions to obtain best quality passion fruit juice powder was 12 % maltodextrin, 8 % corn starch, inlet air temperature of 165 °C, feed pump speed of 12 rpm (0.83 ml/ h), outlet air temperature of 75 °C, blower speed of 1700 rpm and atomizer pressure of 2.5 kg/ cm2 . The optimized powder sample possesses quality attributes of product yield (61.23 %), moisture content (1.62 %), titrable acidity (5.67 %), vitamin C (23.15 mg/100g), total difference in colour (20.37), pH value (6.5), CI index (4.11), hausner ratio (1.043), bulk density (0.513 g/cm3 ), and true density (0.535 g/cm3 ). Particle surface morphology and size of optimized passion fruit juice powder was analysed and estimated using scanning electron microscopy (SEM). Particles were observed as individual particles well separated from each other, with a spherical morphology, a smooth surface, and with 182 likely uniform sizes. The particle size of the spray dried passion fruit juice powder varied from 53.87 µm to 80.39 µm. The optimally produced sample scored a sensory score of 7.91. The storage study was conducted using different packaging materials viz. aluminium laminated pouches and polypropylene pouches at various storage temperatures such as ambient and refrigerated. The spray dried passion fruit powder was safe to be store in aluminium laminated pouches of 150 microns thickness at ambient conditions for three months. The production cost of one kilogram of spray dried passion fruit juice powder was estimated as Rs. 1874/-.
Ozone treatments for improving the quality parameters and surface decontamination of tomato
(Department of Processing and Food Engineering, Kelappaji College of Agricultural Engineering and Technology Tavanur, 2022-04-18) Ardra C Babu.; Rajesh, G K
Minimising pathogenic and spoilage microorganisms in fruits, vegetables and their products are of prime importance in food safety. The consumption of fresh horticultural products is significant as they form an integral part of a perfectly balanced diet due to the presence of numerous essential nutrients, phytochemicals etc which lower the risk of diseases. The superiority in quality has led to its increased consumption, but this surge in usage is accompanied by a rise in food borne outbreaks which in turn makes it important to maintain microbial safety in all activities related to the handling of fresh fruits and vegetables. Tomato (Solanum lycopersicum), an edible berry belonging to the Solanaceae family, is one of the most versatile and a widely consumed fruit due to its abundance in carotenoids, phenolic compounds, ascorbic acid etc. However, they are highly susceptible to the attack of numerous microorganisms. Conventionally, thermal processing methods viz. pasteurisation, sterilisation, frying, cooking etc. are used to inhibit pathogens. Nonetheless, thermal processing methods are found to have a negative impact on various quality characteristics of fresh horticultural produce. Ozone technology is an emerging non-thermal processing method which is highly effective in disinfection of food products with a great potential for enhancing the shelf stability of food products. Ozone destroys pathogens by the progressive oxidation of vital cellular components wherein microbial cell surface is the primary target. The impact of gaseous ozone treatment on various quality characteristics of tomato and its efficacy in removing surface microflora from tomato samples were evaluated. A treatment chamber specifically for treating tomatoes were designed and developed simultaneously. In addition, the optimised samples were packed in perforated PP and perforated PET packets and were stored in room temperature and refrigerated storage for shelf-life analysis. Consequently, response surface methodology was explored to optimise the ozone treatments with three independent variables: ozone concentration (% weight/weight), temperature (℃), treatment time (min). The optimised treatment conditions were 30 % ozone concentration, 10 ℃ temperature and a time of 11.7 min. During storage weight loss, total soluble solids and total plate count of the samples increased whereas, hue angle, firmness, β-carotene, lycopene, and ascorbic acid decreased. However, ozone treated samples stored in perforated PET boxes stored at refrigerated conditions (8 ±2℃) were acceptable till 21 days with better quality attributes, lower weight loss and reduced microbial load. Thus, ozonation treatment retained all the quality parameters of tomato along with a significant reduction in the count of surface microorganisms.
Screw press for cocoa butter extraction
(Department of Processing and Food Engineering, Kelappaji College of Agricultural Engineering and Technology. , Tavanur, 2024-03-06) Shamna, N P; Rajesh, G K
Cocoa butter is a natural fat extracted from cocoa beans. It is one of the main components of chocolate and is known for its unique creamy texture and flavour. To obtain cocoa butter, cocoa pods are first harvested from the cocoa tree and then cocoa beans are separated, fermented and dried. Afterward, the beans are roasted, which helps the development of their characteristic flavour. The roasted beans are then cracked using cocoa bean sheller and the cocoa nibs are separated from the cocoa shell by using winnowing machine. The nibs are then processed to separate the cocoa solids from cocoa butter. Most common method used for the cocoa butter extraction is hydraulic press, which is suitable for large scale cocoa processing. Extraction of cocoa butter is the main problem encountered in the small scale processing of cocoa beans. Hence this study is proposed to develop a suitable equipment system for small scale cocoa processing of cocoa beans. The study mainly concentrated on the development of a screw press type extraction unit for the separation of cocoa butter from cocoa nibs. The developed cocoa butter extractor consists of feed hopper, screw shaft, barrel/expelling chamber, control unit, oil outlet and cake outlet. The extraction of cocoa butter from cocoa nibs is performed by the combined action of temperature and pressure generated inside the barrel. As the material moves, the increasing screw diameter towards the outlet and decreasing volume between barrel and screw result in increased pressure within the press chamber, which ultimately separate the cocoa butter from cocoa nibs. In this study, three different process parameters with three levels were selected for the extraction of cocoa butter viz. barrel temperature (80, 100 and120°C), screw speed (50, 70 and 90rpm) and feed rate (2,3 and 4kg/hr) were optimised using Box-Behnken technique combined with response surface methodology. The optimized process parameters obtained for cocoa butter extraction were barrel temperature (100°C), screw speed (50rpm) and feed rate (4kg/hr). A maximum yield of 40 per cent of cocoa butter could be extracted at optimum condition. Characteristic study of cocoa butter and cocoa powder were carried out to obtain the quality as well as the proximate composition. The shelf life study of cocoa butter was done in polyethylene pouch of 80 micron thickness for a period of 3 months. Various quality parameters of stored butter were determined at regular interval of 30 days for 3 months. The cocoa butter quality parameters viz., iodine number, moisture content, peroxide value, free fatty acid (FFA) and water activity were within the allowable limits even after 3 months of storage. The total production cost of 1kg of cocoa butter was found to be Rs. 788. The developed cocoa butter extractor is economically feasible and commercially exploitable.