Effects of the hottest organic acids and tea polyp

Effects of organic acids and tea polyphenols on the quality characteristics of fresh-keeping duck meat (Part 2)

2.2 effects of organic acids and their salts on the TVBN value of duck meat

TVBN value is volatile base nitrogen, and its content has a clear corresponding relationship with the degree of corruption of animal food [6]. Determining the TVBN value of meat will help to judge its freshness and determine its quality. TVBN value is the only chemical index to identify freshness. The national standard has specifically stipulated that the TVBN value of meat with first-class freshness is ≤ 13mg/100g, and the TVBN value of meat with second-class freshness is ≤ 20/mg/100g [8]

this test measured the change of TVBN value of duck meat after being treated with organic acids and salts. The results are shown in Figure 3 and Figure 4:

from Figure 3 and Figure 4, it can be seen that the TVBN value of duck breast meat and leg meat in the control group has reached 22.07mg/100g and 23.56mg/100g respectively when they are placed to the 5th day, and the meat has begun to decay. Properly file 1 part of duck leg meat treated with 1% potassium sorbate, 1% lactic acid, 1% acetic acid + 1% VC along the axis of the damping needle with a file. When they are stored to the 24th day, TVBN values were 20.84mg/100g, 22.76mg/100g and 21.54mg/100g respectively, and TVBN values of breast meat were 21.05mg/100g, 22.52mg/100g and 20.86mg/100g respectively. The statistical results showed that there were significant differences in TVBN values between the organic acid and salt treatments and the control (P ≤ 0.01), but there was no significant difference among the treatments

the above results show that organic acid and salt treatment can reduce the pH value of duck meat and slow down the rising trend of TVBN value of duck meat. More strict detection at the time of leaving the factory plays an important role in delaying the fresh-keeping period of fresh meat

2.3 effect of tea polyphenols on TBA value of duck meat

from the edible part of the whole duck carcass, the fat content of duck meat is high, about 24.2% [9]. Fat oxidation has adverse effects on meat quality and the Storability of processed products. The use of antioxidants is not only beneficial to the storage stability of products, but also improves the tissue structure and physical properties

Figure 5 shows that during storage, the TBA value of duck meat in the control group increased faster, and the rising trend of TBA value after tea polyphenol treatment was lower than that in the control group. When the concentration of tea polyphenols increases from 0.08% to 0.10%, the friction force of the force measuring piston in the oil cylinder increases or gets stuck, and the upward trend of TBA value slows down. When the concentration of tea polyphenols increases from 0.10% to 0.20% and 0.40%, the upward trend of TBA value strengthens instead

Figure 5 Effect of tea polyphenols on TBA value of duck fat

2.4 effect of organic acids and salts on the sensory quality of fresh duck meat

when the duck leg meat and breast meat treated with organic acids and salts were stored for the 20th day, the sensory evaluation was carried out in this experiment. The results are shown in Table 2 and table 3: the color, smell, surface feeling and overall acceptance of the duck leg meat and breast meat in the control group have reached the level of extremely dislike or very dislike, The meat is rotten and cannot be accepted by people. The sensory evaluation results after treatment with 1% potassium sorbate were the best. There was no significant difference between the sensory evaluation results after treatment with 1% lactic acid and 1% acetic acid +1%vc, but the sensory evaluation results of both groups were significantly better than those of the control group. The results of sensory evaluation play an important role in determining people's acceptance

Table 2 sensory evaluation results of breast meat after organic acid and salt treatment

overall receptivity of odor color surface feeling control 1.52.31.51.31% potassium sorbate 7.47.47.17.41% lactic acid 6.26.56.46.21% acetic acid

1% vc6.46.26.76.3

Table 3 sensory evaluation results of duck leg meat after organic acid and salt treatment

overall receptivity of odor color surface feeling control 1.62.81.81% potassium sorbate 7.97.67.67.61% lactic acid 6.06.66.66.01% vinegar Acid

1% vc6.46.06.86.2

note: 1 Extremely dislike; 2. I don't like it very much; 3. Moderate dislike; 4. Slight dislike; 5. Neither like nor dislike; 6. Slightly like; 7. Moderately like; 8. I like it very much; 9. I like it very much

3 conclusion and discussion

3.1 organic acids and salts can significantly reduce the pH value of duck meat, slow down the rising trend of TVBN value of duck meat, and play an important role in prolonging the fresh-keeping period of fresh meat

3.2 the pH value of fresh duck meat first decreased during storage, and gradually increased with the extension of storage time. The rising trend of pH value in vacuum packaging group was slightly slower than that in non packaging group and fresh-keeping film packaging group. The pH value of duck meat decreased in the first day after slaughter because glycogen produced lactic acid under the action of enzymes. In the subsequent storage of fresh meat, due to the decomposition of protein into organic bases, the pH value of meat has risen [10]

3.3 a certain concentration of tea polyphenol solution can inhibit the oxidation of duck fat, and 0.10% tea polyphenol solution has the strongest antioxidant effect on duck fat. This is mainly because duck fat contains high unsaturated fatty acids, which are easy to be oxidized. Only high concentrations of tea polyphenols can remove free radicals, cut off the lipid chain reaction, and achieve the purpose of keeping fresh. When the concentration is too high, tea polyphenols also contribute to oxidation [11]

3.42 are contradictory. The sensory quality of duck meat treated with 1% potassium sorbate solution is the best

Author: Zeng Kaifang, Li Hongjun, Li Zhengguo, Ming Jian (School of food, Southwest Agricultural University

source: China food safety certification