Progress 10/01/00 to 09/30/05
Outputs
The commercial pressure frying has been limited to frying huge amount of products due to its dependence on the amount of moisture released from the food for generating the desired pressure. This study investigated the feasibility of using nitrogen gas as a substitute for steam in the pressure frying system. The effects of various process conditions on fried products and frying oil qualities were evaluated. Frying experiments were performed on poultry products including chicken nuggets and chicken fillets. Efforts were also made to develop rapid methods to determine oil quality and discriminate among fresh, marginal and discarded oils using a chemosensory or Fourier transform infrared spectroscopy. Crispness is one of the desirable textural characteristics of fried foods. The study investigated the use of ultrasound to evaluate crispness. To improve the crispness of breaded foods fried under pressure, modifications to both frying equipment and product formulation were
explored. Frying temperature and pressure affected fried food quality. Compared to steam, nitrogen provided similar or better quality fried products in terms of moisture retention, juiciness and texture. The reused oil from the fryer using nitrogen gas was better in quality than the system using steam. Mechanical and ultrasonic techniques were used to determine crispness in breaded fried foods under different storage conditions. An eight member panel was trained to evaluate crispness in breaded fried foods. Correlation between sensory crispness and instrumental parameters suggests that the ultrasonic method can be used to evaluate crispness. The ultrasonic velocity had high correlation with sensory crispness (correlation coefficient of 0.83). To improve crispness of breaded fried foods, edible coatings, methylcellulose (MC) and whey protein isolate (WPI) were incorporated into the batter or pre-dust to determine their effect on the crispness of breaded fried chicken nuggets held under
a heat lamp for varying time intervals. Crispness was evaluated by both objective (ultrasonic) and subjective methods. An untrained sensory panel was used to obtain subjective measurements. Panelists rated product attributes such as crispness, juiciness, oiliness and flavor on a simple intensity scale. Products fried with nitrogen gas as the pressurizing medium produced samples that were comparable to or exceeding the quality of products generated by frying with steam, as it relates to product crispness, texture, pressed juice, moisture content, fat content and color. Coating type and application also had a significant effect on product crispness. Samples coated with MC in the pre-dust were crispier than samples coated with WPI. The results of this study demonstrated that applying an edible film coating to the pre-dust and using nitrogen gas as the pressurizing medium can enhance and maintain the crispness of breaded fried foods.
Impacts
This study has demonstrated that frying with nitrogen gas, compared to steaming, and incorporating an edible film coating into the pre-dust significantly increases the crispness of breaded fried chicken nuggets. In addition, there are clear advantages of using nitrogen as a pressurizing medium, including economic benefits due to the extension of the oil fry-life, reduction in product waste from using smaller fry loads and the willingness of consumers to pay a little extra for products fried using nitrogen gas. By adapting the suggested modifications to the existing fryers in the resturants, there could be a significant reduction in oil waste and the resulting value-added products will bring additional revenue to the food industry.
Publications
- Innawong, B., P. Mallikarjunan, J. Marcy and J. Cundiff, 2005. The Effect of Pressure Conditions on Quality of Fried Chicken Nuggets Fried under Gaseous Nitrogen Atmosphere, J. Food Processing Preservation (In Press)
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Progress 10/01/03 to 09/30/04
Outputs
Using nitrogen gas to pressurize the frying chamber, instead of using steam released from the product, produces products with higher moisture retention which can be an issue with product crispness during storage under a heat lamp. Thus, to enhance crispness, use of edible films and coatings in the batter and breading formulations were investigated. The major issue with frying is the use of very high temperatures and recent studies suggest that production of acryl amide in fried foods could be a health issue. Research is underway to study the toxicological effects of acryl amide in humans, which has been identified as a carcinogen in lab rats. Perliminary work to study the effect of frying coniditions on acryl amide formation and using collagen based edible coating to limit oil uptake were conducted. Plans are underway to carry out the experiments in detail in next year.
Impacts
This study has demonstrated that frying with nitrogen gas, compared to steaming, and incorporating an edible film coating into the pre-dust significantly increases the crispness of breaded fried chicken nuggets. In addition, there are clear advantages of using nitrogen as a pressurizing medium, including economic benefits due to the extension of the oil fry-life, reduction in product waste from using smaller fry loads and the willingness of consumers to pay a little extra for products fried using nitrogen gas. By adapting the suggested modifications to the existing fryers in the resturants, there could be a significant reduction in oil waste and the resulting value-added products will bring additional revenue to the food industry.
Publications
- Antonova, I., P. Mallikarjunan, S. E. Duncan, 2004. Sensory assessment of crispness in a breaded fried food held under a heat lamp. Foodservice Research International, 14(3): 189-200.
- Innawong, B., P. Mallikarjunan, J. Irudayaraj and J. E. Marcy. 2003. The determination of frying oil quality using Fourier transform infrared attenuated total reflectance. Lebensmittel-Wissenschaft und-Technologie. 37(1): 23-28.
- Innawong, B., P. Mallikarjunan, and J. E. Marcy. 2003. The determination of frying oil quality using a chemosensory system. Lebensmittel-Wissenschaft und-Technologie. 37(1): 35-41.
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Progress 10/01/02 to 09/30/03
Outputs
In order to investigate the effects of using nitrogen gas on fried product quality, samples were tested using an untrained sensory panel. In addition to the effect of using nitrogen, use of edible coatings to maintain crispness was considered in the study. For extending crispness, methylcellulose (MC) and whey protein isolate (WPI) were incorporated into the batter and pre-dust to determine their effect on crispness of chicken nuggets held under a heat lamp. Both objective and subjective crispness measurements were evaluated. Other quality attributes such as press juice, color, moisture and fat contents were also evaluated. Samples fried with nitrogen gas had significantly higher mean objective crispness values, suggesting the products were crispier than those fried with steam. Additionally, products coated with MC were significantly different from those coated with WPI. Products coated with MC were crispier. The coating application also had a significant effect on
sample crispness. Chicken nugget samples in which the coating was incorporated into the pre-dust were crispier than those samples in which the coating was incorporated into the batter. The results from sensory analysis concluded that there were no significant differences among the samples tested based on crispness, juiciness, oiliness or flavor. Furthermore, there were no significant differences found among samples based on overall liking. However, female subjects preferred products fried with nitrogen gas, as indicated by higher mean ratings for overall liking. Conversely, male subjects did not have a preference. Although no significant differences were found, panelists were willing to pay more for samples fried using nitrogen gas. This study has demonstrated that frying with nitrogen gas as opposed to steam and incorporating an edible film coating (MC was found to be the most effective in this study) into the pre-dust significantly increases the crispness of breaded fried chicken
nuggets. Furthermore, using nitrogen and edible film coatings produces breaded fried products that are comparable to or exceed the quality of those samples fried with steam. In addition, there are clear advantages of using nitrogen as a pressurizing medium including economic gain due to the extension of the oil fry-life, reduction in product waste from using smaller fry loads and the willingness of consumers to pay a little extra for products fried using nitrogen gas.
Impacts
This study has demonstrated that frying with nitrogen gas as opposed to steam and incorporating an edible film coating into the pre-dust significantly increases the crispness of breaded fried chicken nuggets. In addition, there are clear advantages of using nitrogen as a pressurizing medium, including economic gain due to the extension of the oil fry-life, reduction in product waste from using smaller fry loads and the willingness of consumers to pay a little extra for products fried using nitrogen gas. By adapting the suggested modifications to the existing fryers in the resturants, there could be a significant reduction in oil waste and the resulting value-added products will bring additional revenue to the food industry.
Publications
- Antonova, I., P. Mallikarjunan, and S.E. Duncan. 2003. Correlating Objective Measurements of Crispness in Breaded Fried Chicken Nuggets with Sensory Crispness. J. Food Sci. 68(4):1308-1315.
- Innawong, B. and P. Mallikarjunan, 2003. Effect of pressure conditions on the deterioration of frying oil. Paper # 116c, Proceedings of the Eighth Conference of Food Engineeering, San Francisco, CA. Nov 16-21. American Institute of Chemical Engineers, New York, NY.
- Ballard, T. and P. Mallikarjunan, 2003. Crispness enhancement using edible coatings in breaded fried foods. Paper #104d, Proceedings of the Eighth Conference of Food Engineeering, San Francisco, CA. Nov 16-21. American Institute of Chemical Engineers, New York, NY.
- Ballard, T., and P. Mallikarjuan, 2003. Application of edible coatings to maintain crispness in breaded fried foods. Annual IFT Meeting, Chicago, IL. July 12-16. Abstract # 43-3, 2003 Institute of Food Technologists Annual Meeting Book of Abstracts, Chicago, IL.
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Progress 10/01/01 to 09/30/02
Outputs
Crispness is one of the most distinctive textural characteristics of dry crisp and fried products. Samples were finish cooked by one of the three methods: frying, oven heating and microwave heating and samples were held under a heat-warmer lamp or at ambient conditions for up to 40 minutes. Objective parameters using ultrasonic technique and sensory crispness using a trained panel were obtained for fried breaded chicken nuggets. Ultrasonic measurements were made in a transmission mode. Sensory scores were on a 9 point category scale. Significant differences in ultrasonic velocity, transmission loss, peak force, and total energy were observed among the samples cooked by different methods. Ultrasonic velocity had high correlation with sensory crispness. This indicates that the ultrasonic velocity could predict sensory crispness.
Impacts
A non-destructive evaluation of crispness in breaded fried foods was developed. Being non-destructive and rapid, it would save materials, time and the dependence on trained human sensory panels. This method would provide opportunities for the food industry to develop novel frying methods and formulations to improve crispness in breaded fried foods in an objective way. This can also be used as a rapid evaluation method for quality assurance.
Publications
- Antonova, I., Mallikarjunan, P. and Haugh, C. G. 2002. Correlation between instrumental and sensory measurements of crispness in breaded fried chicken nuggets. Journal of Food Science, In Press.
- Innawong, B. and Mallikarjunan, P. 2002. Effect of pressure source and frying conditions on the quality of fried chicken nuggets. Presented at the Annual Meeting of Institute of Food Technologists, Anaheim, CA, June 15-19. Abstract No. 13-12.
- Antonova, I. and Mallikarjunan, P. 2002. Correlation between instrumental and sensory measurements of crispness in breaded fried chicken nuggets. Presented at the Annual Meeting of Institute of Food Technologists, Anaheim, CA, June 15-19. Abstract No. 42-11.
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Progress 10/01/00 to 09/30/01
Outputs
Experiments were conducted to determine the possibility of using a chemosensory system to differentiate among varying intensities of oil rancidity and investigate discrimination between good, marginal and unacceptable frying oils. The discrimination between good, marginal and unacceptable frying oils with regard to rancidity was examined and the results were compared to their physicochemical properties such as dielectric constant, peroxide value (PV), and free fatty acid content (FFA). The different qualities of frying oils were successfully evaluated with good discrimination and stability for identification between acceptable and unacceptable qualities of frying oil. The possibility of using the whole spectra (wave numbers between 4000 and 850 cm-1) from Fourier transform infrared attenuated total reflectance spectroscopy (FTIR-ATR) to differentiate between good, marginal and unacceptable oils with regard to various intensities of oil rancidity was investigated.
Fresh, used, and discarded oils were collected from several fast food restaurants from each frying cycle for 4 weeks. The FTIR data correlated very well with physicochemical measurements. The correlation (r) between FTIR absorbance (3300 cm-1) and FFA was from 0.84 to 0.94 for oils from the three restaurants. Similarly, the correlation (r) between FTIR absorbance (3471 cm-1) and PV was from 0.90 to 0.97 for oils from the same restaurants. The results of the principal component analysis technique (PCA), using the whole spectra (4000 to 850 cm-1) showed good discrimination and stability for identification between acceptable and unacceptable frying oils with regard to rancidity. This study also explored the possibilities of using the ultrasonic non-destructive testing technique to evaluate crispness in breaded fried chicken nuggets. Pairs of dry-coupling ultrasonic transducers at frequencies of 250 kHz were used to perform the ultrasonic transmission on the breaded fried chicken nuggets.
The evaluation of ultrasonic properties was based on analyzing the time domain of the transmitted ultrasound. This study found that ultrasonic parameters such as maximum peak-to-peak amplitude of the signal and ultrasonic velocity varied with the changes in sample properties. The value of maximum peak-to-peak amplitude was found in range of 0.4 - 1.8 V. The value of ultrasonic velocity varied from 0.3 to 1.2 cm/ms. Ultrasonic velocity seems to describe the changes in product crispness. The samples kept under ambient conditions had higher values for velocity than samples held under a heat lamp, which could be due to the lack of crispness in those samples.
Impacts
Frying oil quality can be quantified effectively in a short time and without the need for elobarate sample preparation and data analysis techniques. The developed methods correlate well with the results from conventional experimental techniques and has great potential for developing hand-held instruments to be used in the food industry. The methods developed to measure crispness in breaded fried foods also has great potential for use in the industry.
Publications
- No publications reported this period
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