Effect of tea polyphenols as an antioxidant on pork for frying at different temperatures and times

Abstract

The aim of this study was to investigate the effect of frying on the antioxidant properties of tea phenols added to pork. The antioxidant capacity of tea polyphenols with different concentrations was tested using different assays including total antioxidant capacity (T-AOC) (FRAP method), thiobarbituric acid reactive substance, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging, and 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) radical scavenging. Our results indicated that tea polyphenols have a great antioxidant capacity and that a high frying temperature causes fat oxidation. Our study confirmed that DPPH assay is more suited to lipophilic compounds or compounds with high lipid content. In a frying temperature of 180°C, the DPPH-free radical scavenging ability of pork was not decreased. Further experiments remain necessary to explore specific temperatures with the same results. This study provides new process parameters and new references for processing techniques of healthy and high-quality pork products.

Keywords: antioxidants; cooking; frying; tea polyphenols.

FIGURE 1

T‐AOC assay standard curve.

FIGURE 2

MDA assay standard curve.

FIGURE 3

Effect of tea polyphenols on T‐AOC due to frying at different temperatures and times for pork samples. The data points without same superscripts (A, B) are significantly different (one‐way ANOVA). Letters represent differences in different groups, such as capital letters at the level of p < .01 by least significant difference (LSD) test; Lower case letter at the level of p < .05 by least significant difference (LSD) test. C group: Control group, the natural chilled pork; TP₁ group: in 6 g/L of tea polyphenols 1 L at 4°C overnight before cooking; TP₂ group: in 9 g/L of tea polyphenols 1 L at 4°C overnight before cooking; TP₃ group: in 12 g/L of tea polyphenols 1 L at 4°C overnight before cooking.

FIGURE 4

Effect of Tea Polyphenols on TRABS due to frying at Different temperatures and times for pork samples. The data points without same superscripts (A, B) are significantly different (one‐way ANOVA). Letters represent differences in different groups, such as capital letters at the level of p < .01 by least significant difference (LSD) test; Lower case letter at the level of p < .05 by least significant difference (LSD) test. C group: Control group, the natural chilled pork; TP₁ group: in 6 g/L of tea polyphenols 1 L at 4°C overnight before cooking; TP₂ group: in 9 g/L of tea polyphenols 1 L at 4°C overnight before cooking; TP₃ group: in 12 g/L of tea polyphenols 1 L at 4°C overnight before cooking.

FIGURE 5

Effect of tea polyphenols on weight loss at different temperatures and times for pork samples. The data points without same superscripts (A, B) are significantly different (one‐way ANOVA). Letters represent differences in different groups, such as capital letters at the level of p < .01 by least significant difference (LSD) test; Lower case letter at the level of p < .05 by least significant difference (LSD) test. C group: Control group, the natural chilled pork; TP₁ group: in 6 g/L of tea polyphenols 1 L at 4°C overnight before cooking; TP₂ group: in 9 g/L of tea polyphenols 1 L at 4°C overnight before cooking; TP₃ group: in 12 g/L of tea polyphenols 1 L at 4°C overnight before cooking.

FIGURE 6

Effect of tea polyphenols on DPPH free radical scavenging ability at different temperatures and times for pork samples. The data points without same superscripts (A, B) are significantly different (one‐way ANOVA). Letters represent differences in different groups, such as capital letters at the level of p < .01 by least significant difference (LSD) test; Lower case letter at the level of p < .05 by least significant difference (LSD) test. C group: Control group, the natural chilled pork; TP₁ group: in 6 g/L of tea polyphenols 1 L at 4°C overnight before cooking; TP₂ group: in 9 g/L of tea polyphenols 1 L at 4°C overnight before cooking; TP₃ group: in 12 g/L of tea polyphenols 1 L at 4°C overnight before cooking.

FIGURE 7

Effect of tea polyphenols on ABTS⁺ free radical scavenging ability at different temperatures and times for pork samples. The data points without same superscripts (A, B) are significantly different (one‐way ANOVA). Letters represent differences in different groups, such as capital letters at the level of p < .01 by least significant difference (LSD) test; Lower case letter at the level of p < .05 by least significant difference (LSD) test. C group: Control group, the natural chilled pork; TP₁ group: in 6 g/L of tea polyphenols 1 L at 4°C overnight before cooking; TP₂ group: in 9 g/L of tea polyphenols 1 L at 4°C overnight before cooking; TP₃ group: in 12 g/L of tea polyphenols 1 L at 4°C overnight before cooking.