Application of computer vision and electronic nose technologies for quality assessment of color and odor of shrimp and salmon

Current techniques for shrimp and salmon quality evaluations rely on sensory methods. These procedures are subjective, prone to error, and difficult to quantify. Chemical analyses are seldom used by the seafood industry due to the complexity and length of time these methods require. Automated evaluation of color and odor is desirable to reduce subjectivity and discrepancies and assist with the creation of standards for inspectors worldwide. The objectives of this study were to develop color machine vision techniques for visual evaluation and to test electronic nose sensors for odor assessment of raw and cooked shrimp and fresh raw salmon.; A color machine vision system was developed to analyze the color of seafood samples. Hardware consisted of a light box, a video camera, and a frame grabber. Software developed for the Windows environment was able to determine the color of food samples by discretizing the RGB (red, green, blue) color system into 64, 512, or 4096 colors, and by giving color information in different color scales (RGB, L*a*b*, XYZ, or Munsell). The system was able to analyze the color of samples with non-uniform color surfaces, to predict the amount of melanosis (black spots) in shrimp, and to measure color changes of shrimp and salmon during storage.; An electronic nose with twelve conducting polymer sensors was used to measure odors of shrimp and salmon stored at different temperatures, with different levels of spoilage, and treated with Merent chemicals. Discriminant function analysis was used as the pattern recognition technique to differentiate samples based on odors. Results showed that the electronic nose could discriminate differences in odor due to storage time and spoilage levels for shrimp and salmon, and species and food additives in shrimp. Results also showed good correlation of sensor readings with sensory scores and chemical concentrations. Overall, the electronic nose showed good sensitivity and accuracy.; Results from this work could lead to methodologies that will assist in the objective and repeatable quality evaluation of shrimp and salmon. These methods have potential in industrial and regulatory applications where rapid response, no sample preparation, and no need for chemicals are required. Furthermore, expertise in sensory evaluation may be captured and used by instruments.