Effects of green tea leaf, lotus leaf, and kimchi powders on quality characteristics of chicken liver sausages

Liver sausage is flavorful and highly nutritious. However, liver has a relatively short shelf life due to acceleration of oxidation in the presence of endogenous enzymes and metals. Powders derived from natural sources, including plants or fruits, are applied to meat products for inhibiting oxidation without adverse effects on their quality. Hence, this study investigated the effects of natural powders derived from green tea leaf (GTL), lotus leaf (LL), and kimchi (KC) on the quality and change in lipid oxidation and freshness of chicken liver sausages during two weeks of storage. Chicken liver sausages were manufactured with chicken breast (70%) and liver (20%), pork back fat (5%), iced water (5%), various additives, and GTL, LL, and KC [0 (control) or 1%]. They were processed in three batches. For determination of the quality characteristics of chicken liver sausages with various plant powders, pH, color, and texture properties were assessed. In addition, lipid oxidation and freshness using thiobarbituric acid reactive substances (TBARS) and total volatile basic nitrogen (TVBN) were analyzed at day 0 and week 2 of refrigerated storage. Higher values were obtained for pH and cooking yield in sausage samples with LL and KC powders than in samples with the other treatments. For a* values, the sausage samples with KC showed similar (p > 0.05) values, whilst others had significantly lower values than the control. The addition of the three powders to sausage samples induced an increase (p < 0.05) in hardness, gumminess, and chewiness. The addition of plant powders did not influence TBARS and TVBN of sausage samples at the initial stage. However, after two weeks of storage, significantly lower TBARS and TVBN values were observed, and the sausage with KC (p < 0.05) showed the lowest values of both TBARS and TVBN. The results showed the potential ability of the three powders to improve the quality and inhibit lipid oxidation in liver sausages. Particularly, the addition of KC did not adversely affect the a* values of sausage samples. The effects on sensory properties and inhibition mechanisms of GTL, LL, and KC in meat products should be further studied

Impacts of post-mortem ageing prior to freezing on technological and oxidative properties of coarse ground lamb sausage in a model system

Objective The objective of this study was to evaluate the effects of ageing time of lamb loins prior to freezing on technological characteristics and oxidation stability of coarse ground lamb loin sausage using in a model system. Methods Lamb loins (M. longissimus lumborum, n = 25) were aged at −1.5°C for 0, 1, 2, 3, and 8 wk and then frozen for the remaining days (a total of 30 wk). The aged/frozen/thawed lamb loins were ground, and model sausages were formulated with 75% aged/frozen/thawed lamb loin, 25% water, 1.5% sodium chloride (NaCl) and 0.3% sodium tripolyphosphate. The pH and thaw/purge loss of aged/frozen/thawed lamb loins were evaluated, and protein functionality (protein solubility and emulsifying capacity), water-holding capacity and textural properties of model sausages were determined. Cooked model sausages were vacuum-packaged in a plastic bag and displayed under continuous fluorescent natural white light (3°C±1°C). Colour and lipid oxidation of the cooked model sausages were evaluated on 0 and 21 d of display storage. Results Ageing prior to freezing had no impact on pH and purge/thaw loss of lamb loins and the colour of cooked sausages (p>0.05) made from the loins. Lamb loins aged for at least 3 wk prior to freezing numerically improved total and myofibrillar protein solubilities (p>0.05) and emulsion activity index (p = 0.009) of meat batter, but decreased cooking loss (p = 0.003) and lipid oxidation (p<0.05) of model sausages. Conclusion This study suggests that post-mortem ageing of raw meat prior to freezing could improve water-holding capacity and lipid oxidative stability of sausage made from the meat

Antioxidant effects of lotus (Nelumbo nucifera) root and leaf extracts and their application on pork patties as inhibitors of lipid oxidation, alone and in combination

Different antioxidant mechanisms of lotus root and leaf were exhibited against lipid oxidation. The effect of lotus root (LRE) and leaf (LLE) extracted with 50% ethanol exhibited high antioxidant activities. It also improved quality and/or oxidative stability of pork patties when extracts were applied individually (1%) or in combination (each 0.5%). The pork patties treated with either LLE or that with LRE exhibited significantly lower peroxide and 2-thiobarbituric acid reactive substances (TBARS) value than the control and patties with LRE. However, the lowest TBARS values were observed in patties with LLE alone from day 7 among the treatments. Patties treated with both LRE and LLE had the highest score in off flavor (P< 0.05). Hence, the combined effect of LRE and LLE was uncertain and the addition of 1% LLE in patties showed superior antioxidant activity during storage days with an adverse effect on quality properties, except for color

Isolation and identification of angiotensin I-converting enzyme inhibitory peptides derived from thermolysin-injected beef

Objective This study identified angiotensin I-converting enzyme (ACE) inhibitory peptides in beef M. longissimus injected with thermolysin (80 ppm) and stored for 3 days at 5°C. Methods Crude peptides (molecular weight <3 kDa) were obtained from the thermolysin hydrolysate and separated into seven fractions. Fraction V showing the highest ACE inhibitory activity was further fractionated, yielding subfractions V-15, V-m1, and V-m2, and selected for superior ACE inhibitory activity. Finally, twelve peptides were identified from the three peak fractions and the ACE inhibitory activity (IC50) of each peptide was evaluated. Results The Leu-Ser-Trp, Phe-Gly-Tyr, and Tyr-Arg-Gln peptides exhibited the strongest ACE inhibitory activity (IC50 values of 0.89, 2.69, and 3.09 mM, respectively) and had higher concentrations (6.63, 10.60, and 29.91 pg/g; p<0.05) relative to the other peptides tested. Conclusion These results suggest that the thermolysin injection process is beneficial to the generation of bioactive peptides with strong ACE inhibitory activity

Bioactivities of peptide fractions derived from proteolytic enzyme-injected Hanwoo longissimus muscle in a model system

In this study, crude peptide fractions from Hanwoo loins were released by injecting with proteolytic enzymes [no enzymes (control); protease type XIII (E1); thermolysin (E2); and combination of E1 and E2 (E3)] and their bioactivities were determined. The peptides derived from E2-injected Hanwoo loin exhibited the highest angiotensin I–converting enzyme (ACE) inhibitory activity and vitamin C equivalents antioxidant capacity among the treatments. The released peptide by treatment of E2 and E3 had similar (P > 0.05) inhibitory activity in HT29 cancer cell viability compared with luteolin as a positive control and non-cytotoxic effect on normal cell (3T3-L1). Therefore, the released peptide fraction from thermolysin (E2)-injected Hanwoo beef might contain potent bioactive peptides with ACE inhibitory and antioxidative activity and inhibition effect on certain cancer cell viability

Analysis of low-marbled Hanwoo cow meat aged with different dry-aging methods

Objective Different dry-aging methods [traditional dry-aging (TD), simplified dry-aging (SD), and SD in an aging bag (SDB)] were compared to investigate the possible use of SD and/or SDB in practical situations. Methods Sirloins from 48 Hanwoo cows were frozen (Control, 2 days postmortem) or dry-aged for 28 days using the different aging methods and analyzed for chemical composition, total aerobic bacterial count, shear force, inosine 5′-monophosphate (IMP) and free amino acid content, and sensory properties. Results The difference in chemical composition, total aerobic bacterial count, shear force, IMP, and total free amino acid content were negligible among the 3 dry-aged groups. The SD and SDB showed statistically similar tenderness, flavor, and overall acceptability relative to TD. However, SDB had a relatively higher saleable yield. Conclusion Both SD and SDB can successfully substitute for TD. However, SDB would be the best option for simplified dry-aging of low-marbled beef with a relatively high saleable yield