Progress 01/15/05 to 01/14/09
OUTPUTS: We have successfully accomplished the originally proposed objectives: 1) to develop a technique that can measure the degree of fiber formation objectively and 2) to understand protein-protein interactions and fiber formation mechanism. We first developed an image processing technique based on Hough transform to calculate the fiber formation index in soy protein extrusions. This method provided a quantitative and objective alternative to human visual inspection. For nondestructive and online monitoring, we developed a novel technique based on a photon migration model in anisotropic samples. This technique was further improved to scan the entire sample surface by incorporating a laser scanning system. The system was tested to confirm its reliability and real-time scanning was successfully conducted to demonstrate its capability. Using the isoelectric focus buffer with omission of one or more selective reagents, we determined the protein solubility of samples collected at different extruder zones and extrudates made with different moistures. Results indicate that disulfide bonding plays a more important role than non-covalent bonds in not only holding the rigid structure of extrudates but also forming fibrous texture. PARTICIPANTS: Hsieh, F. and Yao, G. Professor and Associate Professor, Department of Biological Engineering, University of Missouri, Columbia, MO 65211-5200. MacDonald. R. Professor and Chair, Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011. TARGET AUDIENCES: Food companies producing soy protein isolate, soy protein concentrate, defatted soy flour, wheat gluten, and wheat starch such as Cargill, ADM, Solae, Bunge, and MGP Ingredients, etc. PROJECT MODIFICATIONS: Not relevant to this project.
This new fast scanning system is non-contact and non-destructive. It has robust performance against ambient light and is ideally positioned as an online, real-time method for quantifying fiber formation in high moisture extrusion products. The usefulness of this imaging system is being evaluated by a Fortune 100 company. Two students completed their MS in Food Science are now working in food industry and one student, completed PhD in Biological Engineering, is starting his post-doctoral training in imaging area.
- Ranasinghesagara J., Hsieh, F., and Yao, G. (2005). Quantifying fiber formation in meat analogs under high moisture extrusion using image processing. Proc. SPIE 5996:140-147.
- Ranasinghesagara J., Hsieh, F., and Yao, G. (2005). An image processing method for quantifying fiber formation in meat analogs under high moisture extrusion. J Food Sci.70:E450-454.
- Ranasinghesagara J., Hsieh, F., and Yao, G. (2006). Characterizing fiber formation in meat analogs using an anisotropic photon migration model. Proc. SPIE 6381,13.
- Ranasinghesagara J., Hsiehm F., and Yao, G. (2006). A photon migration method for quantifying fiber formation in meat analogs. J Food Sci.71: E227-231.
- Liu, K. and Hsieh, F. (2007). Protein-protein interactions in high moisture-extruded meat analogs and heat-induced soy protein gels. J. Am. Oil Chem. Soc., 84(8):741-748.
- Liu, K. and Hsieh, F. (2008). Protein-protein interactions during high moisture extrusions of fibrous meat analogs and comparison of protein solubility methods using different solvent systems. J. Agric. Food Chem., 56(8):2681-2687.
- Ranasinghesagara J., Hsieh, F., and Yao, G. (2009). Non-destructive real time monitoring of fiber formation in meat analogs. Proc. SPIE 7315, 12.
- Ranasinghesagara J., Hsieh, F., Huff, H.E., and Yao, G. (2009). A laser scanning system for real-time mapping of fiber formations in meat analogs. J. Food Sci., in press.
Progress 01/15/07 to 01/14/08
OUTPUTS: Continuing our previous work on monitoring fiber formation in extrudates, we have expanded our imaging system into a 2-dimentional scanning system. We are now able to map both the fiber formation information and fiber orientation onto the whole sample surface. We also improved our numerical algorithm in order to achieve real-time speed. A new laser scanning system has been constructed with supporting real-time software to acquire and analyze images. The system will be tested on the pilot extrusion machine in PI's lab. A total of 20 male and 20 female mice were separated into groups of 10 and fed a diet made with either a commercial soy protein or the experimental extruded soy protein meat analog for 90 days. Throughout the feeding trial the body weight and food intake were recorded. At termination, blood was obtained and organ dissected and weighed. The blood was analyzed for cortisol, IGF-1, growth hormone and insulin. Bone mineral content and breaking strength were
measured. Colon histology was quantified. No effect of diet was observed on growth as determined by body weight. Of the parameters measured, there was an overall diet effect on liver weight, cecum weight, femur width and femur mineral content. Gender effects were observed for most parameters and a diet*gender interaction was observed for colon crypt height, hematocrit, femur width and femur breaking strength. Within gender, a diet effect was observed for males in femur width only, and for females in colon crypt height and liver weight. A detailed report of the data is in preparation.
PARTICIPANTS: Hsieh, F. and Yao, G. Professor and Assistant Professor, Department of Biological Engineering, University of Missouri, Columbia, MO 65211-5200. MacDonald, R. Professor and Chair, Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011.
TARGET AUDIENCES: Food companies producing soy protein isolate, soy protein concentrate, and defatted soy flours such as Cargill, ADM, Solae, and Bunge, etc.
PROJECT MODIFICATIONS: None.
The usefulness of the imaging method developed in this project to quantitatively evaluate the degree of fiber formation in the soy protein meat analog is currently being evaluated by a Fortune 100 company located in the St. Louis area. Two students completed their Master of Science degrees in Food Science. They are not only knowledgeable in extrusion cooking of high moisture meat analog but also are skillful in the operation of a twin-screw extruder. They are ready for working in the food industry and making their contributions.
- Liu, K. and Hsieh, F. (2007). Protein-protein interactions in high moisture-extruded meat analogs and heat-induced soy protein gels. J. Am. Oil Chem. Soc., 84:741-748.
- Advalli, S. (2007). Extrusion and Physicochemical Properties of Soy-Whey Protein Meat Analog. M.S. Thesis, University of Missouri, Columbia, MO.
- Chiang, A. (2007). Protein-Protein Interaction of Soy Protein Isolate from Extrusion Cooking. M.S. Thesis, University of Missouri, Columbia, MO.
Progress 01/15/06 to 01/15/07
Extended from our previous studies, we developed a novel technique to quantify fiber formation in meat analogs. The method was based on a photon migration model in anisotropic samples. An imaging system was constructed to capture the point-spread images of light incident upon the sample. An imaging processing model and a numerical fitting algorithm were developed to characterize the equi-intensity profiles of reflectance images. The calculated parameters were then converted into a single numerical fiber index. Experimental studies showed this method can provide accurate assessment on fiber formation in soy protein meat analogs. The obtained fiber index had good correlation with that measured using a destructive image processing method. Two commercial soy protein isolates were extruded into fibrous meat analogs under high moisture conditions. Protein gels at two concentrations were also made by heating isolate dispersions followed by cooling. Extrudates were about 10
times harder than gels. Protein-protein interactions as a result of extrusion and gelation were investigated by protein solubility study and compared. In general, all samples except for extrudates exhibited similar solubility patterns by 4 selected extractants. Phosphate buffer (PB) extracted the least amount of protein. Addition of dithiothreitol (DTT) improved protein solubility, indicating the presence of disulfide bonds. PB+Urea, and PB+Urea+DTT gave the highest and almost equal amount of extractable proteins for all samples except for the extrudates from which protein could not be extracted effectively by PB+Urea, implying that disulfide bonding is more pronounced during extrusion than gelation. The results support our hypothesis that both soy protein gels and extrudates have the same types of chemical bonds, namely covalent disulfide bonds and non-covalent interactions. What sets the two apart from each other in terms of thermal reversibility and structure rigidity is the
relative proportion of each type of bonds in their structures. Protein gels primarily consist of non-covalent bonds, but the disulfide bond is also partially responsible; whereas for forming the fibrous structure of soy protein extrudates, both non-covalent bonds and covalent disulfide bonds are important.
This new fiber quantification technique is non-contact and non-destructive. It has robust performance against ambient light and is ideally positioned as a online, real-time method for quantifying fiber formation in high moisture extrusion products.
- J. Ranasinghesagara, F. Hsieh, and G. Yao. A photon migration method for quantifying fiber formation in meat analogs. J Food Sci.71:E227-231(2006).
- J. Ranasinghesagara, F. Hsieh, and G. Yao. Characterizing Fiber Formation in Meat Analogs using an Anisotropic Photon Migration Model. Optics East'07, Proc. SPIE 6381-13(2006).
Progress 01/15/05 to 01/14/06
Soy protein meat analog was produced using a twin-screw extruder attached with a cooling die. The experimental design consisted of two cooling die widths (30 and 60 mm), two cooling die lengths (100 and 300 mm), four product moisture contents (71.2, 67.0, 61.6 and 55.8% w.b.), and two cooling media (water or water plus ethylene glycol). The equivalent overall heat transfer coefficient between extruded product and cooling die was estimated based on three-channel split-flow heat transfer analysis. Product temperatures at the die outlet were predicted with the estimated value of Ue. The values of Ue varied in the range of 0.204 - 0.326 and 0.221 - 0.307 kW/m2K for water and water plus ethylene glycol, respectively, depending on die width and feed moisture content. Predicted product temperatures at the die outlet were within the difference of 8.8C from measured experimental values.
The magnitude of the equivalent heat transfer coefficient in the cooling die will influence the design and the performance of the cooling die for the process scale-up. It could also be used to predict of the temperature of product exiting from the cooling die, which affects the quality of meat analog.
- Lee, G.H., Huff, H.E. and Hsieh, F. 2005. Overall heat transfer coefficient between cooling die and extruded product. Trans. ASAE 48(4):1461-1469.