Progress 03/01/02 to 02/28/07
Outputs
Investigator retired from the University of Georgia effective August 2005.
Impacts
No report.
Publications
- No publications reported this period
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Progress 01/01/04 to 12/31/04
Outputs
Nutrient Considerations of Extrusion on n-3 Fatty Acids and Vitamin E in a Fish, Rice, Menhaden Oil Formulation: The nutrient content and health benefits of the food we eat has become a prime consideration in food selection by consumers and is therefore rapidly becoming an important tool in marketing of new food products. Functional foods (nutriceuticals) play an important role in this new nutritional awareness. Since polyunsaturated n-3 fatty acids are now accepted functional food components, an extruded product with enhanced n-3 fatty acids content would benefit consumers as well as be a marketing tool. In order to produce a high n-3 fatty acid product suitable for extrusion, a mixture of 25% fish protein concentrate, 73% rice flour and 2% manhaden oil was developed which provided 300mg n-3 fatty acids /28g (db). This formulation was extruded in a twin-screw extruder (25:1 l/d) at 125-145 C, 150-300 rpm screw speed and 19-23% moisture. Eicosapentaenoic acid (EPA),
and docosahexanoic acid(DHA) and vitamin E were analyzed by GLC and normal phase HPLC respectively. The greatest retention of EPA and DHA n-3 fatty acids was at high moisture levels and high screw speeds. The maximum retention of achieved was 94% with DHA showing somewhat higher retention than EPA. Very significant losses (24-46%) of vitamin E were observed, probably due to vitamin E's activity as an anti-oxidant thereby protecting the polyunsaturated fatty acids. The work did show, however, that polyunsaturated n-3 fatty acids can successfully be incorporated into fortified formulated extruded foods.
Impacts
Demonstration that extruded food and snack products can successfully be fortified with n-3 polyunsaturated fatty acid and vitamin E can lead to significant health benefits in consumers of such products.
Publications
- Abegaz, E.B., Kerr, W.L., and Koehler, P. E. 2004. The role of Moisture in Flavor changes of Model Peanut Butter Confections during Storage. Lebensmittel-Wissenschaft und-Technolgie 37: 215-225.
- Song, L.H. 2004. Plant sterols and antioxidants in Ginko biloba and Quercus species. Ph.D. Dissertation. University of Georgia. Athens, GA.
- Fatouh, A.E., Singh, R.K., and Koehler, P. E. 2004. Physical, Chemical and Stability Properties of Buffalo Butter Oil Fractions Obtained by Multi-step Dry Fractionation. Food Chemistry 89: 243-252.
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Progress 01/01/03 to 12/31/03
Outputs
Induction of the Pink Color Defect in Cooked Chicken Breast Muscle During Processing: Pinking (pink tinge) in fully cooked poultry products is one of the quality defects that face the poultry processing industry. Chicken pieces with this defect retain a pink color even after the meat has reached the 71 deg C. temperature required by the USDA Food Safety and Inspection Service. The defect is responsible for substantial losses to the poultry industry. Samples of three color groups (normal, lighter than normal, darker than normal) of raw boneless skinless chicken breast muscles were selected. Color changes induced in each of these raw chicken breasts categories by treatments with combinations of sodium chloride, sodium tripolyphosphate, sodium erythorbate or sodium nitrite were evaluated. The presence of sodium nitrite had the most significant effect on pinking causing the defect at levels as low as 1 ppm. Simulation of the pink defect was achieved in eight of 16
treatment combinations when sodium nitrite was present but in only two treatment conbinations when sodium nitrite was absent. The pinking effect was most pronounced in the darker than normal raw chicken breasts. The initial lightness (CIE L*) of the raw muscle was the most critical color parameter for predicting the occurrence of pinking in cooked muscle. In samples injected with as little as 4 ppm sodium nitrite, the a* value doubled while the CIE hue angle (hue angle=arctan(b*/a*) decreased from 81 to 67 degrees. A comparison of results from visual examination and colorimetric data established the subjective pink threshold at a*=3.8. This is slightly lower than than the a* value of >4 reported previously to indicate pinking. Pinking in fully cooked samples was affected (P<0.05) by the CIE L* value of the raw meat color. The selection of samples into three color groups (light, normal, and dark) was important since the lightness of raw muscles may indicate different initial endogenous
conditions of meat (pH for example) which respond differently to the experimental processing conditions. Reflectance spectra measurements of the meat surfaces was made to provide information whether the presence of the pink defect could be related to the presence of certain heme pigments.
Impacts
Consumers who expect an off-white hue in uncured fully cooked chicken white meat consider even a slight pinkness as an indication of an undercooked product. Pinking (pink tinge) in fully cooked poultry products is a quality defects that face the poultry processing industry. Knowledge of processing parameters which can effect the pink color defect in the cooked product can prevent substantial losses to the poultry processing industry due to rejection of the cooked chicken product.
Publications
- Fatouh, A.E., Singh, R.K., Koehler, P. E., Mahran, G.A., El-Ghandour, and Metwally, A.E. 2003. Chemical and Thermal Characteristics of Buffalo Butter Oil Fractions Obtained by Multi-step Dry Fractionation. Lebensmittle-Wissenschaft und-Technologie 36: 483-496.
- Holownia, K. Chinnan, M.S., Reynolds, A.E. and Koehler, P.E. 2003 Evaluation of Induced Color changes in Chicken Breast Meat During Simulation of Pink Color Defect. Poultry Sci. 82: 1049-1059.
- Abegaz, E. G., Kerr, W.L. and Koehler, P. E. 2003. Peanut Flavor Fade. The Manufacturing Confectioner 82(9): 95-102.
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Progress 01/01/02 to 12/31/02
Outputs
Monascus purpureus pigments as yoghurt colorants: Colorants are often added by manufacturers to fruit flavored yoghurt to enhance or to replace the natural color of the fruit. Pigments produced by the mold, Monascus purpureus, offer a possible alternative to the FD&C certified food dyes or natural pigments now used. Monascus pigment were studied to ascertain their performance as coloring agents for yoghurt in comparison with more traditional red yoghurt colorants. The color of commercial strawberry yoghurts colored with either FD&C Red #40, beetpowder, carmine, or a carmine/annato mix were measured as L,a,b with a Minolta CR-300 Colorimeter and compared with yoghurts prepared with Monascus pigments as colorants. Color changes (L, Hue angle, and chroma) in the Monascus colored yoghurt during processing from milk to yoghurt were determined and compared with changes experienced using more traditional colorants. Commercial strawberry yoghurts vary greatly in color. L
values ranged from 68 to 83, hue angle from 21 to 53 and chroma values from 8 to 15 suggesting a wide range of acceptable color for strawberry yoghurt. Increasing the Monascus pigment concentrations from 0.125% to 0.375% decreased L values from 69 to 61, increased the chroma from 10 to 16, and changed the hue angle from 33 to 21 degrees. Yoghurt manufactured with Monascus pigments as colorants closely matched commercial samples of strawberry yoghurt. Color matches could be obtained with, delta-E values(color differences) of less than 1.0. While color did change during yoghurt manufacture, the changes in Monascus-colored yoghurt were comparable to that of FD&C Red 40 and was actually less changes in carmine and beet juice powder under the same conditions. Changes during shelf-life storage were noted but the Monascus-colored yoghurt showed less change in hue angle than either Red 40 or beet juice. There was no significant difference in the decline in pH during 21 days. Also, over 21
days, the numbers of Lactobacillus and Streptococcus were the same in the uncolored control and the Monascus colored yoghurt. The mean force (0.230N) at first peak measured on an Instron Universal Testing Machine was identical in the control and Monascus-colored yoghurt indicating that the textures were similar. Monascus purpureus could be an acceptable substitute for traditional colorants in strawberry yoghurt. While the color does change somewhat during various production steps, the change is comparable to that of FD&C Red#40, and is less that the changes found using carmine or beet juice powder.
Impacts
Monascus purpureus could be used by yoghurt manufacturers as an acceptable natural color substitute for synthetic dyes in strawberry yoghurt providing better color while maintaining the all-natural attributes desired by many yoghurt consumers.
Publications
- No publications reported this period
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