Study On The Compound Bio-Preservative For Surimi-Based Products

Surimi-based products are favored by consumers at home and abroad and have become one of the fastest growing aquatic products in China, because of their rich nutrition, affordable price and convenient to eat. However, due to the higher moisture content and rich nutrition, surimi-based products are very easy to suffer microbiological spoilage. At present, most of surimi-based products stored in frozen (-18℃or below), which is energy consuming, high cost and can damage the quality. If the current storage mode was changed to preserve at around 0℃, the good quality of surimi-based products will be kept, and a lot of energy and cost will be saved. Therefore, the study of preservation of surimi-based products has been paid more and more attention. Biological preservation techniques offer a good opportunity for the realization of the preservation of surimi-based products.Based on those above reasons, the preservation of surimi-based products was studied in this paper. Three kinds of the biological preservatives, tea polyphenols, water-soluble chitosan and Nisin, were selected by tests of inhibiting bacteria activity. The optimal concentrations of the three kinds of biological preservatives were determined by the storage experiments. The optimal ratio of those three compound bio-preservatives was obtained by response surface analysis. Then, the effects of compound bio-preservative on the quality of fish ball were investigated based on sensory, physical, chemical and microbiological changes during the storage. At last, spectral characteristics of fish ball were studied using near-infrared spectroscopy.The results were shown as follow:1. Tea polyphenols, water-soluble chitosan and Nisin were screened as the final bio-preservatives for surimi-based products. It was showed that adding tea polyphenols, water-soluble chitosan and Nisin could extend the shelf life of fish-ball by 7,14 and 5 days respectively, compared with the control group. Adding those three bio-preservatives could improve the texture of fish ball, including enhances hardness and maintains springiness. The freshness were also could be kept at a good level, indicated by the relative low TBA, TVB-N and pH values. The optimal additions of tea polyphenols, water-soluble chitosan and Nisin were 0.2～0.3 g/kg,4.0～5.0 g/kg.0.4～0.5 g/kg.2. The optimum proportion of the compound bio-preservatives was determined, according to Box-Behnken central composite design principles. The optimal addition of tea polyphenols, water-soluble chitosan, and Nisin were 0.2133 g/kg,5.4850 g/kg and 0.4280 g/kg respectively. The results showed that compound bio-preservative could inhibit the growth of microorganisms in fish ball significantly during storage and the total number of bacteria was lower than 104 CFU/kg at 42nd day. Meanwhile, a good sensory and texture quality of fish ball were kept. Compound bio-preservative could maintain steady pH values, prevent acidification of the fat and degradation of protein, and enable the TBA and TVB-N values at a low level relatively. The basic components, such as fat, protein content, amino acid composition, moisture and water activity of fish ball were not significant changed after adding the compound bio-preservatives (p＜0.05). In addition, the result of test by environmental scanning electron microscopy (ESEM) showed that gel structure became uniform, and gel surface became more homogeneous and dense after adding compound bio-preservative. Adding compound bio-preservative could improve the flavor offish ball, according the detection results of gas chromatography-mass spectrometric (GC-MS).3. A correlation model between texture characteristics and near-infrared spectra was established. The results of validation showed that the model showed a good fitness, indicating that the model could perfectly reflect the relationship between texture characteristics and near-infrared spectra. Adding water-soluble chitosan could affect the near-infrared spectroscopy and texture characteristics. The model could distinguish whether the samples were added water-soluble chitosan.