SBIR-STTR Award

Papaya is a major commodity in Hawaii. The Big Island accounted for about 35.7 million of harvested papaya for fresh utilization and 1.8 million pounds for processed utilization. Additional processed utilization of papaya would be valuable to the industry because culls average 30 percent of total harvested papayas. It is estimated the culls that can be processed annually from the independent packinghouses would be over 4 million pounds. Utilization of these papayas would greatly benefit the packinghouses and in turn produce additional farm gate and improve the economy of the state's rural communities. The purpose of this project is to prove the feasibility of a processing concept, incorporating ozone and heat treatment anti-microbial technologies along with flash freezing, that not only addresses food safety, but also enhances the quality and flavor of the fruit. The project focuses on reducing the microbial counts and enzymatic actions as well as eliminating any freezing problems due to the high amount of "bound" water in papayas. Bound water remains unfrozen until temperatures are below minus 4 degrees Fahrenheit. Improper freezing of papayas causes a watery, soft product of poor quality. OBJECTIVES: Our goal is to utilize culled papayas grown in Hawaii and produce a consistently high quality Individual Quick Frozen (IQF) product that is devoid of off-flavor and off-aroma and sufficiently stable to retain its value during frozen storage. The objectives of this project is to evaluate the effectiveness that ozone treatment, in conjunction with heat treatment, as microbial reducing methods and flash freezing have on reducing microbial growth and ensuring a high sensory quality frozen product made from culled papayas. This project is designed to answer the following questions: 1. What is the optimal ozone ppm level and time of immersion for microbial reduction? 2. Can the Enterobacter cloacae count be reduced sufficiently? 3. Can the Sodexho standard pathogenic, ACP and coliform counts be achieved by combining ozone treatment with heat treatment microbial reducing methods? 4. Can flash freezing eliminate the potential problem of bounded water and produce a product with no drip? 5. Can freezing further reduce the microbial counts and maintain fruit sensory quality and for what length of time? APPROACH: The basic approach to develop an IQF papaya product is a six-step process: 1. Sort fruits by visually inspecting for color and damage and, for those suitable for processing, treat the whole papaya as a GMP sanitization measure. 2. Peel, slice/deseed, and cube the fruit into the desired size. By careful removal of the seeds from the cavity of papaya much of the off-flavor and off-aroma of benzylisothiocyanate can be prevented. Peeling and cubing the papaya produces more surface area for ozone treatment and greatly diminishes disparity and the lag phase in heat transfer resulting in shortened heat treatment and freezing times. 3. Treat the cubed fruit with an ozone wash as a GMP sanitization measure and to reduce the initial microbial count for heat treatment. Using the principles of thermobacteriology of first order death kinetics, a reduced initial microbial load through the use of the ozone treatment results in reduced subsequent heat temperature and treatment times. 4. Treat the cubed fruit with vapor heat. As mentioned earlier, using an ozone wash on the cubed fruit we were able to get a 2-D reduction in the coliform count with E. cloacae as the principal problem. With steps (2) and (3) as preliminary procedures, possible adverse effects on texture and flavor due to this approach is not expected as the proposed heat treatments are within the realm of the quarantine heat treatments which are currently being used commercially without adverse effects. The regulation for quarantine vapor heat treatment is 117 degrees Fahrenheit; however, in actuality some of the papayas in the chamber reach an internal temperature of 118.4 degrees Fahrenheit for one hour. From this report the heat processing to achieve 5-D microbial reduction can be determined. 5. Treat the cubed fruit with a chilled ozone wash as a GMP sanitization measure, to stop the cooking process, and to reduce the temperature of the fruit prior to flash freezing. This results in a shortened time to reach an internal temperature of below minus 4 degrees Fahrenheit. 6. Flash freeze the product to below minus 4 degrees Fahrenheit and vacuum seal the product.

Papaya is a major fruit commodity in Hawaii with over 28 million pounds utilized in 2006. 26.6 million pounds of the harvested papaya are used for fresh utilization and 2.3 million pounds for processed utilization. Processed utilization is currently for aseptic puree produced by a single processor. Additional processing of papaya would be valuable because there are an estimated 3.5 million pounds of culls that can be utilized annually. If not processed into puree, there is no income to the farmer and the packinghouse must dispose of the culls by discarding them, giving them away for livestock feed, or selling them in bulk to a broker for local utilization. The purpose of this project is to utilize these culled papayas and produce a consistently high quality, nutritional Individual Quick Frozen (IQF) product with increased food safety and sufficient stability to retain its value during frozen storage. Utilization of papaya culls would greatly benefit the Hawaii papaya industry and improve the economy of the state's rural communities. Successful project completion will result in a sound, proven concept for processing culled papayas into an IFQ product. This will ensure the microbial security of the product, eliminate the need for quarantine treatment, and preserve fruit quality. An IQF product would provide the industry another avenue to the export market rather than having the culls discarded or sold in the local market. This would allow the industry to establish a niche and compete in the $300 million frozen fruit market. OBJECTIVES: Our goal is to utilize culled papayas grown in Hawaii and produce a consistently high quality Individual Quick Frozen (IQF) product that has excellent sensory qualities and sufficiently stable to retain its value during frozen storage. The objectives of this project is to evaluate the effectiveness that ozone treatment, in conjunction with heat treatment, as microbial reducing methods and the effectiveness of flash freezing in producing a high quality frozen product. The project is designed to answer the following questions: (1) What is the optimal ozone ppm level and time of immersion for microbial reduction; (2) Can the Enterobacter cloacae count be reduced sufficiently; (3) Can the Sodexho standard pathogenic, ACP and coliform counts be achieved by combining ozone treatment with heat treatment microbial reducing methods; (4) Can flash freezing eliminate the potential problem of bounded water and produce a product with no drip; and (5) Can freezing further reduce the microbial counts and maintain fruit sensory quality and for what length of time The overall technical objective of this Phase II application is focused on the technical issues observed during Phase I and on the market research needed for Phase III commercialization. The technical issues observed during Phase I are (1) evaluating the vapor heat process using higher relative humidity (RH) during the heating process to increase the rate of heat transfer, (2) conducting larger volume testing to optimize the time/temperature of the freezing requirements, (3) evaluating the softening of the fruit tissue that may occur during delays between cubing and heating and heating and freezing, and (4) evaluating the storage temperature and the shelf-life of the frozen product. The objectives of Phase II are to answer the following questions: Can the microbial reduction be increased and/or the time of treatment be reduced by using higher relative humidity (RH) currently used in commercial vapor heat quarantine treatment equipment during the heating process and maintain fruit quality; What is the effect of improving the freezing process and using equipment with better heat transfer capabilities; Can cold-storage further reduce the microbial counts and maintain fruit quality and for what length of time; What is the layout and operational requirements for commercial manufacturing; and What is the marketability and economic feasibility The expected output of this project is a layout of a commercial process that not only determines the throughput within the vapor heat and freezing processes but the throughput requirements between each stage of processing including cold storage so that economic feasibility can be assessed. The successful accomplishment of Phase II will allow IQF Dream, LLC to establish a manufacturing process, incorporating technologies new to the Big Island papaya industry, that not only addresses food safety, quarantine regulations and shelf life, but that also enhances the sensory quality of the fruit. APPROACH: The basic approach to develop an IQF papaya product follows a ten-step process:(1) Choose Kapoho and Rainbow cultivars suitable for processing at the packinghouse. Discard fruits that show visual signs of damage to reduce the incidence of postharvest diseases. (2) Transport chosen papayas to ripening storage area. Select from storage area three quarter to full ripe papayas for processing to capture the best qualities of the fruit.(3) Prior to entry into preparation room, wash the whole fruit using 100-ppm hypochlorite solution and rinse as a GMP sanitization measure. (4) In the certified preparation room, manually slice papayas in half lengthwise. Discard any hard flesh papayas and those showing internal yellowing, purple stain and any other visual diseases/bruising and cleanse utensils. Discarding these papayas will eliminate high initial loads of Enterobacter cloacae and other pathogens. (5) Deseed, slice papaya lengthwise into eights, cube the flesh into the desired size, and peel. By careful removal of the seeds from the cavity of papaya much of the sulfuric off-odors of benzylisothiocyanate can be prevented. Peeling and cubing the fruit produces more surface area for ozone treatment and greatly diminishes disparity and the lag phase in heat transfer resulting in shortened heat treatment and freezing times. (6) Treat the cubed fruit with an ozone wash as a GMP sanitization measure and to reduce the initial microbial count for heat treatment. Using the principles of thermobacteriology of first order death kinetics, a reduced initial microbial load through the selection of sound papayas and the use of the ozone treatment results in reduced subsequent heat temperature and/or treatment times. (7) Treat the cubed fruit with vapor heat. With steps (4) to (6) as preliminary procedures, possible adverse effects on texture and flavor due to this approach is not expected as the proposed heat treatments are within the realm of the quarantine heat treatments which are currently being used commercially for fresh papaya without adverse effects. (8) Treat the cubed fruit with a chilled ozone wash as a GMP sanitization measure and to reduce the temperature of the fruit prior to flash freezing resulting in a shortened time to reach an internal temperature of -28o C. (9) Flash freeze the individual papaya cubes to -28o C and vacuum seal the product. (10) Store packaged frozen products in boxes at a cold-store temperature of -18o C, -20o C or -23o C. While accomplishing various tests using this procedure, we will evaluate the effects of increased humidity in the vapor heat treatment, evaluate the effects of improving the freezing process by controlling the initial temperature of the papaya cubes, evaluate commercial scale volume processing, and evaluate cold storage performance. We will also evaluate the economic feasibility of the product production