| With the rapid development of the global economy and medical technology, population aging has become a universal phenomenon. China, having the largest number of elderly people, witnesses an aging rate ranking among the top in the world. Despite the large elderly population, the market lacks food specifically designed to meet the safety and nutritional needs of the elderly. Thus, the development of food for the elderly has become a research hotspot. In 2018, the National Health Commission of China released the "National Food Safety Standard - General Rules for Elderly Food" (draft for soliciting opinions), aiming to regulate the production and quality standards of elderly food. It classifies elderly food into easily consumable food, elderly nutritional formula food, and elderly nutritional supplement food, and sets specific nutritional requirements for them. Experts have proposed principles for developing elderly food, including providing sufficient high-quality protein, dietary fiber, vitamins, and trace elements, while emphasizing low-fat, low-sugar, low-calorie, and low-cholesterol formula designs. Additionally, the texture, sensory, and packaging suitability during food processing are also considered to meet the physiological and psychological needs of the elderly. Compared with the international market, the elderly food market in China is still in its infancy, mainly selling health products at present. The variety of daily foods suitable for the elderly is relatively limited, mainly including milk powder, pastries, and biscuits. Although these foods are easy to eat and swallow, they often lack sufficient nutritional value and are difficult to fully meet the nutritional needs of the elderly. Research has shown that the content of vitamins and folic acid in domestic prepackaged elderly food is insufficient, and the content of carbohydrates and energy is often on the high side, increasing the risk of obesity and cardiovascular and cerebrovascular diseases for the elderly with a lower metabolic rate.
Taking advantage of the high economic value, high nutritional value, and delicious taste of seabass (Lateolabrax japonicus), whose fish meat is a source of high-quality protein with low fat content, soft texture, and easy chewability, making it suitable as a raw material for elderly food. This study developed an easily chewable and digestible seabass slippery by adding carrot powder, celery powder, and inulin based on the dietary needs of the elderly. Single-factor experiments and response surface methodology were used, with hardness and sensory scores as indicators to determine the optimal addition ratios of the three nutrient powders. The textural characteristics and nutritional indicators of the product were analyzed. With textural characteristics, sensory evaluation, volatile basic nitrogen content (TVB-N), thiobarbituric acid value (TBA), and total colony count as evaluation indicators, the effects of different packaging methods (regular packaging and vacuum packaging) and different refrigeration temperatures (4°C and -2°C) on the quality of sea bass slippery.
The results showed that the optimal addition amounts of nutrients for sea bass slippery were determined to be carrot powder 1.15%, celery powder 1.10%, and inulin 1.00%. The slippery contained 15.24g of protein and 5.73g of fat per 100g. Its amino acid profile aligning with the ideal protein pattern recommended by FAO/WHO. Moreover, the sea bass slippery contained 18 kinds of fatty acids, with the relative content of unsaturated fatty acids reaching 72.1%, and the total content of EPA and DHA accounting for 11.12%. Determination of seven vitamins in sea bass slippery revealed that sea bass slippery contained the highest amount of vitamin E at 3.54 mg/100g, followed by niacin at 3.48 mg/100g. It exhibited a moderate texture, good water retention, and is easily chewable, making it suitable for elderly consumption. During the first 20 days of storage, the hardness of sea bass slippery gradually increased, but there was no significant difference between the two groups (4℃ and -2℃). However, the hardness of the vacuum-packed sea bass slips continued to increase up to 30 days of storage, while the hardness of the regular packing decreased sharply. Storage experiments demonstrated that vacuum packaging could effectively delay the increase of TVB-N value, TBA value, and total colony count, maintaining the quality of the sea bass slippery. The TVB-N value of regular packaging sea bass slippery was close to the limit value of 30 mg/100 g after 30 days, whereas vacuum- packing sea bass slippery stored at -2°C was still below 13 mg/100 g (within the range of Class I products). The fat oxidation of the fish slippery was higher than that of the vacuum- packing group in all the regular packing conditions, which indicated that the vacuum packing was effective in slowing down the fat oxidation process. Vacuum-packed sea bass slippery can be stored for 7 days at 4°C and 15 days at -2°C, showing a significantly superior preservation effect compared to regular packaging. In conclusion, this research not only introduces a nutritious and healthy food option for the elderly but also presents novel insights for the deep processing and high-value utilization of sea bass, offering technical support and a reference for the diversification and development of marine fish products. |
