Effect of Mulberry Leaf Extracts on Color, Lipid Oxidation, Antioxidant Enzyme Activities and Oxidative Breakdown Products of Raw Ground Beef During Refrigerated Storage

Abstract

The study investigated the effects of mulberry leaf extracts (MLE) on the color, lipid oxidation, antioxidant enzyme activities and oxidative breakdown products of raw ground beef during refrigerated storage. The five treatments were: MLE at 0, 100, 500 and 1,000 lg/g muscle (C, low concentration mulberry leaves extracts (LM), medium concentration mulberry leaves extracts (MM) and high concentration mulberry leaves extracts (HM)) and positive control with 20 lg Vitamin E/g muscle (VE). MLE maintained color, reduced peroxide and thiobarbituric acid reactive substances values during storage (P < 0.05) with no effect on free thiol. MLE increased activities of superoxide dismutase and glutathione peroxidase at 312 h (P < 0.05). There were more phospholipids from the HM treatment than the control group (P < 0.05); unsaturated fatty acids and reducing sugars in the VE group were higher than the C group (P < 0.05). The results indicated that MLE could better use as natural antioxidants to maintain the meat quality, extend shelf-life and prevent economic loss for food processing industry. In addition, one interesting finding was that the antioxidant mechanism of MLE was different comparing to VE during the different stages of lipid oxidation, which MLE worked at the first step and VE protected the second step when phospholipid was decomposed into unsaturated fatty acids. Therefore, we could conclude that it would be better to combine the MLE and VE to protect the meat quality during refrigerated storage. PRACTICAL APPLICATIONSMulberry leaves were rich in alkaloids, polyphenols, flavonoids and anthocyanins, which could be responsible for health benefits as well as herbal medicine for many years in various cultures. Some studies had found that MLE had the antioxidant activities. However, scientific information about the antioxidant properties of MLE in meat and their influence on meat quality is still scarce. The results indicate that MLE have the antioxidant activity, helping maintain the meat color, inhibiting lipid oxidant and enhancing antioxidant enzyme activity. In addition, the antioxidant mechanism of MLE protected phospholipids from oxidation and VE mainly protected the unsaturated fatty acids and reducing sugars. This research explains the antioxidant mechanism of MLE could better use as natural antioxidants to maintain the meat quality, extend shelf-life and prevent economic loss for food processing industry.

Effects of chitosan coating combined with essential oils on quality and antioxidant enzyme activities of grass carp (Ctenopharyngodon idellus) fillets stored at 4 °C

“…Similar result was reported by Zhang et al . (), who found that the higher activities of total SOD and GSH‐px were detected in raw beef treated with mulberry leaf extract compared to that of control during refrigerated storage. The different protective effect on antioxidant enzyme activities was observed in treatments of Ch + clo, Ch + cin and Ch + lem, which might considerably depend on the components of essential oils.…”

Lipid Oxidation, Color Changes, and Microbiological Quality of Frozen Beef Burgers Incorporated with Shirazi Thyme, Cinnamon, and Rosemary Extracts

“…The color of meat products and meat is influenced by metmyoglobin percentage in muscle. Initially, the myoglobin was changed into oxymyoglobin (light pink color), which could result in brighter red meat, and then oxymyoglobin was oxidized into metmyoglobin during storage [7].…”

“…1,1,3,3-tetraethoxypropane was used to develop the standard curve for TBARS assay. TBARS values were reported as mg of malonaldehyde per kg of beef burger [7].…”

“…Therefore, the application of natural antioxidants (such as herbal essential oils and extracts) is of interest and can be observed in a growing number of research works [6][7][8] ( Aliakbarlu et al 2016). Moreover, consumers are increasingly demanding for green-labeled food products such as those containing natural antioxidant.…”

Natural Preservatives to Improve Food Quality and Safety

“…Synthetic antioxidants such as BHT, TBHQ, and BHA have demonstrated various adverse effects on the human health including allergy, headache, asthma, and dermatitis. Recent studies on the utilization of natural antioxidants (e.g., herbal essential oils and extracts) indicate their capacity and safety [3,4]. Also, the antimicrobial properties of natural substances such as plant essential oils and extracts have been extensively studied with promising results [5].…”