Effects of aqueous antioxidants extracts from ginger, garlic and onion on 2-thiobarbituric Acid Reactive Substances and total volatile basic nitrogen content in chevon (goat meat) and pork during frozen storage

Abstract The study investigated the effect of 10% aqueous extracts of ginger ( Zingiber officinale L.), garlic ( Allium sativum L.) and onion ( Allium cepa L.) on the quality of frozen chevon and pork as reflected by changes in values of 2-thiobartituric Acid Reactive Substances (2-TBARS), pH and total volatile basic nitrogen (TVB-N) over a 14 day storage under frozen conditions. Fresh samples each weighing 2 kg from chevon and pork were bought from the local slaughter houses in two locations 24hrs after slaughtering while ginger roots, garlic and onion bulbs were purchased from Mitundu local market in Lilongwe district, Malawi. The pH, total 2-TBARS and TVB-N of the thigh chevon and pork were measured from frozen storage at −20 °C after 14 days. The 10% aqueous extracts resulted in low pH values of 5.63, 5.79 and 5.67 at 14 d for chevon mixed with ginger, garlic and onion respectively. However, treated pork had higher pH content compared to treated chevon at 14 d. At day14 of frozen storage, the 2-TBARS expressed as mg MDA/kg meat, for chevon mixed with ginger, garlic and onion aqueous extracts were 2.62±0.01, 0 and 4.71±0.03 which was lower compared to the value of 5.93±0.01 for raw chevon. The TBARS values of chevon and pork mixed with ginger, garlic and onion and control chevon decreased from day 0 to 7 which eventually increased on 14 d. On 14 d, pork mixed with garlic extracts had lower TBARS value of 2.13±0.01 compared to 3.50±0.20, 2.26±0.01 and 3.92±0.01 for pork mixed with extracts of onion, ginger and control pork sample respectively. TVB-N, in mg/100g, was highest in control raw chevon and pork registering 95.70±0.32 and 84.00±0.40 at 14 d. Low values of TVB-N of 7.24±0.23, 12.37±0.23 and 16.61v±0.50 were registered in chevon mixed with aqueous extracts of ginger, garlic and onion compared to the values of 14.23±0.62, 22.87±0.47 and 18.86±0.14 for pork mixed with aqueous extracts of ginger, garlic and onion. The results of the study have revealed that natural aqueous antioxidant extracts of ginger, garlic and onion have antioxidative effect on lipid peroxidation in frozen stored fresh chevon and pork signifying that the use of these extracts can maintain quality.