Effect of coating with combined chitosan and gallic acid on shelf-life stability of Jeju black cattle beef

OBJECTIVE

Beef of Jeju black cattle (JBC) is considered as a healthy meat type due to its significantly higher unsaturated fatty acids (UFA). Lipid (e.g., UFA) is highly susceptible to oxidizing agents, which results in the quality deterioration and economic value loss of meat products. Therefore, development and application of novel preservative techniques is necessary to improve the shelf-life stability of high-UFA beef. The objective of this study was to assess the applicability of chitosan-based coatings in preservation of JBC beef.

METHODS

Different coating solutions: 2% chitosan alone, and 2% chitosan containing 0.1% or 0.3% gallic acid were prepared to investigate their applicability in preservation of fresh beef during storage. Jeju black cattle beef (2-cm thick steaks) were non-coated (control) or coated with the above coating solutions, placed on trays, over-wrapped with plastic film and stored at 4°C. The microbiological indices, color, total volatile basic nitrogen (TVBN) and lipid oxidation of the beef were investigated after 1, 10, and 21 days of storage.

RESULTS

Coating with 2% chitosan alone reduced the spoilage bacteria count, TVBN and thiobarbituric acid reactive substances levels in the beef compared with control during storage (p<0.05). Noticeably, coating with 2% chitosan containing 0.1% or 0.3% gallic acid was more effective on retardation of spoilage bacteria growth, lipid oxidation and discoloration in the beef compared to the chitosan coating alone over the storage period (21 days) (p<0.05).

CONCLUSION

Taken together, the combined chitosan and gallic acid coating could be used as a bio-preservative technique in the meat industry.

Dual mechanism of silver nanoparticle-mediated upregulation of adipogenesis in mouse fibroblasts (3T3-L1) in vitro

Silver nanoparticles (AgNPs) are widespread in the environment due to the increase in their application e.g. in medicine as part of hard-to-heal wound dressings. Many studies have revealed easy diffusion of AgNPs into deep skin layers through damaged epidermis and contact with e.g. fibroblasts. Therefore, the aim of this study was to evaluate the impact of small-size AgNPs (10 nm) in ppm concentrations on the adipogenesis process in mouse embryo fibroblasts (3T3-L1). The results showed a decrease in the metabolic activity, followed by an increase in the reactive oxygen species (ROS) level in a dose- and time-dependent manner (0-20 ppm). The increased caspase-3 activity was observed only at the highest concentration (20 ppm) of AgNPs. Further analysis showed the ability of the tested NPs to increase the lipid accumulation in adipocytes, similar to ROSI [peroxisome proliferator-activated receptor gamma (PPARγ) agonist], measured by Oil-Red-O staining. Moreover, the analyses evidenced the ability of AgNPs to increase the lipoxygenase activity and malondialdehyde levels, which is probably based on ROS-dependent enhancement of lipid hydroperoxidation. Lastly, a significant increase in the PPARγ, Adiponectin, Resistin, Vegf, and Serpine mRNA expression was shown 6 h after the induction of the differentiation process. Based on the obtained results, it can be concluded that small-size AgNPs increase adipogenesis via ROS- and PPARγ-based mechanisms with potential engagement of crosstalk with the aryl hydrocarbon receptor, which is important due to the widespread application of AgNPs in medicine. However, more studies are needed to elucidate the full mechanism of these NPs in the tested cell model in depth.

Migration of tocopherols from the oil phase to the oil-water interface using phospholipids improved the oxidative stability of O/W emulsions

The purpose of this research was to effectively migrate tocopherols (T) to the oil-water interface layer (oxidation site) by combining hydrophobic T with amphiphilic phospholipids (P) to improve the oxidative stability of O/W emulsions. Firstly, it was confirmed that the antioxidant ability of TP combinations exhibited synergistic effects in O/W emulsions by measuring lipid hydroperoxides and thiobarbituric acid-reactive species. Moreover, the introduction of P into O/W emulsions to improve the distribution of T at the interfacial layer was confirmed by centrifugation and confocal microscopy methods. Subsequently, the possible mechanisms of synergistic interaction between T and P were described by fluorescence spectroscopy, isothermal titration calorimetry, electron spin resonance, quantum chemical methods and the variation of minor constituents during storage. This research revealed an in-depth insight into the antioxidant interaction mechanism of TP combinations using experimental and theoretical approaches, which provided theoretical guidance for developing emulsion products with better oxidative stability.

Cooked broiler meat quality affected by different Mediterranean medicinal plants in the diet

Objective

This study was conducted to investigate the effects of adding oregano (Origanum syriacum L.) and germander (Teucrium polium L.) to poultry diets individually and/or in combination: i) on cooked chicken meat quality and storage stability, ii) to compare this effect with those of the synthetic antioxidant butylated hydroxyanisole (BHA) and with the normal basic diet (Control: without supplements).

Methods

Broilers (140 birds) were raised for 21 days and then equally divided into five different treatment groups of 28 birds each. The dietary treatments were as follows: i) control; ii) germander (GER, 1.5%); iii) oregano (ORE, 2.5%); iv) combination of GER and ORE (CM, 1.5%, and 2.5%); v) BHA (0.02%). Meat patties from the five treatments were prepared, cooked, and stored at 4°C prior to analysis. During storage, samples were measured for thiobarbituric acid-reactive substances (TBARS) and total carbonyl levels at 0, 4, and 7 days. In addition, cooked thigh meat was prepared separately to evaluate cooking loss and sensory attributes.

Results

The CM dietary treatment showed the highest antioxidant effect, with decreasing TBARS values (breast and thigh meat) throughout the storage time (4 to 7 days). Furthermore, ORE showed a higher antioxidant effect, decreasing the rancidity development (TBARS values), compared to the GER during the storage period (days 0 to 7). The anti-carbonyl effect of the CM supplement was the highest among all treatments from day 0 to 7. Generally, the antioxidant effect of GER was lower compared to that of ORE and BHA alone. The CM treatment most significantly decreased off-odor and rancidity development, with the lowest oxidation odor scores.

Conclusion

The results indicate that the combination of oregano and germander in the diet of boilers improves meat quality and prolongs shelf life.

Effect of myoglobin, hemin, and ferric iron on quality of chicken breast meat

OBJECTIVE

The objective was to evaluate the impact of different forms of iron including myoglobin, hemin, and ferric chloride on the quality of chicken breast meat.

METHODS

Chicken breast muscles were subjected to 1, 2, 3 mg/mL of FeCl3, myoglobin and hemin treatment respectively, and the production of reactive oxygen species (ROS) and malondialdehyde, meat color, tenderness, water holding capacity and morphology of meat was evaluated.

RESULTS

Hemin was found to produce more ROS and induce greater extent of lipid oxidation than myoglobin and ferric chloride. However, it showed that hemin could significantly increase the redness and decrease the lightness of the muscle. Hemin was also shown to be prominent in improving water holding capacity of meat, maintaining a relatively higher level of the immobilized water from low-field nuclear magnetic resonance measurements. Morphology observation by hematoxylin-eosin staining further confirmed the results that hemin preserved the integrity of the muscle.

CONCLUSION

The results indicated that hemin may have economic benefit for the industry based on its advantage in improving water holding capacity and quality of meat.

31 P NMR assessment of the phosvitin-iron complex in mayonnaise

Lipid oxidation is the main reason for the limited shelf life of mayonnaise. One of the main catalysts of this process is iron, which is introduced in its ferric (Fe(III)) form via phosvitin, an egg yolk phosphoprotein rich in phosphoserines. The binding of Fe(III) to phosvitin and its ability to establish a redox couple with Fe(II) is believed to determine the oxidation rate of unsaturated lipids. In this work, a ³¹ P NMR based method was developed to quantify loading of phosvitin with Fe(III) and its reductive release. Both features could be quantified in model phosvitin solutions by exploiting the paramagnetic broadening of ³¹ P NMR signal of phosphoserine residues by Fe(III). This method was then successfully applied to quantify the phosvitin-Fe(III) loading in mayonnaise water phase by liquid NMR, whereas ³¹ P NMR MAS could only provide a qualitative measure. The ³¹ P NMR method showed a direct relation between loading of the Fe(III)-phosvitin complex and lipid oxidation.

Effect of aged garlic powder on physicochemical characteristics, texture profiles, and oxidative stability of ready-to-eat pork patties

Objective

The aim of this study was to investigate the effects of aged garlic powder (AGP) on physicochemical characteristics, texture profiles, and oxidative stability of ready-to-eat (RTE) pork patties.

Methods

There were five treatment groups: a control; 1% fresh garlic powder (T1); 0.5%, 1%, and 2% AGP (T2, T3, and T4). Pork patties with vacuum packaging were roasted at 71°C for core temperature, stored at 4°C for 14 d, and then reheated for 1 min using a microwave.

Results

The AGP groups showed a lower the level of lipid oxidation and higher thiol contents than the control and T1. The pH value of the control increased whereas that of aged garlic groups decreased after re-heating process. In addition, the redness significantly increased with increasing level of AGP whereas the redness of the control and T1 decreased after re-heating process. T4 added patties improved textural and sensory properties compared to the control.

Conclusion

The results of this study suggest that AGP addition to RTE pork patties can improve their sensory characteristics and oxidative stability.

Inhibition of lipid and protein oxidation in raw ground pork by Terminalia arjuna fruit extract during refrigerated storage

OBJECTIVE

Terminalia arjuna plant, specially its leaves, bark, and roots, are widely used in traditional herbal medicine due to presence of bioactive components and being a rich source of natural antioxidants. But its fruit has not been used for any such purposes despite its potential to retard oxidation. Hence, the antioxidant potential of Arjuna fruit extract (AFE) in retarding lipid and protein oxidation of raw ground pork was evaluated during refrigerated storage for 9 days.

METHODS

The AFEs were prepared using different solvents viz. ethanol (EH), water, ethanol: water (60:40) and methanol:hot water (60:40). The AFEs were analysed for total phenolic content (TPC), 2, 2-diphenyl-1-picrylhydrazyl radical scavenging activity and reducing power. Water extract (WE) and ethanol-water extract (EH-WE) were selected and incorporated at 1.0% into freshly minced pork meat and compared with a synthetic antioxidant, in retarding lipid and protein oxidation during storage.

RESULTS

The TPC in AFEs using different solvents ranged from 11.04 to 16.53 mg gallic acid equivalents/g and extracts exhibited appreciable scavenging activity ranging from 50.02% to 58.62%. Arjuna extracts significantly (p<0.05) improved the colour score of meat samples by reducing the formation of metmyoglobin during storage. Both the AFEs (WE and EH-WE) significantly (p<0.05) lowered the thiobarbituric acid reactive substances value, peroxide formation and formation of protein carbonyls in raw pork than control sample during storage. Upon sensory evaluation of all samples, it was found that AFE treatment could prolong the storage period of meat samples, without influencing the colour and odour score, up to 6 days.

CONCLUSION

AFEs used at 1% improved the oxidative stability, colour and odour score and prolonged the refrigerated shelf life of ground pork up 6 days. Therefore, AFE could be explored as an alternative natural antioxidant in retarding lipid and protein oxidation in meat products.

Rubber seed oil and flaxseed oil supplementation on serum fatty acid profile, oxidation stability of serum and milk, and immune function of dairy cows

Objective

This study was designed to investigate the effect of diet supplementation with rubber seed oil and flaxseed oil on serum fatty acids profile, oxidation stability of serum and milk, and immune function of dairy cows.

Methods

Forty-eight mid-lactation Holstein dairy cows were randomly assigned to one of four treatments for 8 wk, including basal diet (CON) or the basal diet supplemented with 4% rubber seed oil (RO), 4% flaxseed oil (FO) or 2% rubber seed oil plus 2% flaxseed oil (RFO) on a dry matter basis.

Results

Compared with CON, all the oil groups increased the levels of trans-11 C18:1 (vaccenic acid), cis-9, trans-11 C18:2 (conjugated linoleic acid, CLA) and C18:3 (α-linolenic acid, ALA) in serum. Both the activity of glutathione peroxidase and catalase in serum and milk in oil groups were decreased, which were negatively correlated with the levels of cis-9, trans-11 CLA and ALA. The concentrations of proinflammatory factors (tumor necrosis factor α and interferon γ) in serum of oil groups were lower than that from the CON cows.

Conclusion

These results indicate that diet supplementation with RO or FO could alter serum fatty acid profile and enhance the immune function of dairy cows. However, the negative effect on milk oxidation stability should be considered when feeding these n-3 polyunsaturated fatty acid-enriched oils in dairy production.

Assessment of frozen storage duration effect on quality characteristics of various horse muscles

Objective

The study aimed at assessing the effects of frozen storage duration on quality characteristics, lipid oxidation and sensory quality of various horse muscles.

Methods

Five representative muscles: longissimus dorsi (LD), gluteus medius (GM), semimembranosus (SM), biceps femoris (BF), and triceps brachii (TB) at 24 h post-mortem obtained from 28-mo-old Jeju female breed horses (n = 8) were used in the present investigation. The muscles were vacuum-packaged and frozen at −20°C for 120, 240, and 360 days. All the samples were analyzed for thawing and cooking losses, pH, Warner–Bratzler shear forces (WBSF), color traits, total volatile basic nitrogen (TVBN), thiobarbituric acid reactive substances (TBARS) and sensory traits. The muscle samples analyzed on day 0 of frozen storage (fresh, non-frozen) were used for comparison.

Results

Results revealed that thawing and cooking losses significantly (p<0.05) increased in all the muscles after 120 days and then remained unchanged up to 360 days of frozen storage. The TBARS and TVBN contents significantly increased as increasing frozen storage time up to 360 days (p<0.05). While, significant decreases in WBSF values were observed for all the muscles with increased frozen storage time (p<0.05). Frozen storage variously affected the color traits of the muscles for instance; the redness of LD, GM, and BF muscles showed a decreasing tendency during frozen storage while it was not changed in TB and SM muscles. Furthermore, the frozen storage did not produce detrimental effects on sensory quality as it did not cause flavor and juiciness defects whereas it partially improved the tenderness of all the muscles studied.

Conclusion

Based on the results obtained from our work, it is concluded that frozen storage could be applied to increase the long-term shelf life of horsemeat while still retaining its sensory quality.

Effects of cooking method and final core-temperature on cooking loss, lipid oxidation, nucleotide-related compounds and aroma volatiles of Hanwoo brisket

OBJECTIVE

This study observed the effects of cooking method and final core temperature on cooking loss, lipid oxidation, aroma volatiles, nucleotide-related compounds and aroma volatiles of Hanwoo brisket (deep pectoralis).

METHODS

Deep pectoralis muscles (8.65% of crude fat) were obtained from three Hanwoo steer carcasses with 1⁺ quality grade. Samples were either oven-roasted at 180°C (dry heat) or cooked in boiling water (moist heat) to final core temperature of 70°C (medium) or 77°C (well-done).

RESULTS

Boiling method reduced more fat but retained more moisture than did the oven roasting method (p<0.001), thus no significant differences were found on cooking loss. However, samples lost more weight as final core temperature increased (p<0.01). Further, total saturated fatty acid increased (p = 0.02) while total monounsaturated fatty acid decreased (p = 0.03) as final core temperature increased. Regardless the method used for cooking, malondialdehyde (p<0.01) and free iron contents (p<0.001) were observed higher in samples cooked to 77°C. Oven roasting retained more inosinic acid, inosine and hypoxanthine in samples than did the boiling method (p<0.001), of which the concentration decreased as final core temperature increased except for hypoxanthine. Samples cooked to 77°C using oven roasting method released more intense aroma than did the others and the aroma pattern was discriminated based on the intensity. Most of aldehydes and pyrazines were more abundant in oven-roasted samples than in boiled samples. Among identified volatiles, hexanal had the highest area unit in both boiled and oven-roasted samples, of which the abundance increased as the final core temperature increased.

CONCLUSION

The boiling method extracted inosinic acid and rendered fat from beef brisket, whereas oven roasting intensified aroma derived from aldehydes and pyrazines and prevented the extreme loss of inosinic acid.

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 Enzyme Activity, Iron Content and Lipid Oxidation of Raw and Cooked Meat of Korean Native Chickens and Other Poultry

This study was conducted to observe antioxidant enzyme activity, iron content and lipid oxidation of Korean native chickens and other poultry. The breast and thigh meat of three Korean native chicken breeds including Woorimatdak, Hyunin black and Yeonsan ogye, and three commercial poultry breeds including the broiler, White Leghorn and Pekin duck (Anasplatyrhyncos domesticus) were studied. The analyses of the antioxidant enzymes activity, iron content and lipid oxidation were performed in raw and cooked samples. The activity of catalase (CAT) in the thigh meat was higher than that of the breast meat of three Korean native chickens and the broiler, respectively. The activity of glutathione peroxidase (GPx) in the uncooked thigh meat of three Korean native chickens was higher than that of the breasts. The breast meat of Woorimatdak and Pekin duck had higher superoxide dismutase (SOD) activity than the others, while only the thigh meat of Pekin duck had the highest activity. Cooking inactivated CAT and decreased the activity of GPx and SOD. The thigh meat of Woorimatdak, White Leghorn, Yeonsan ogye and Hyunin black contained more total iron than the breast meat of those breeds. The heme-iron lost during cooking ranged from 3.2% to 14.8%. It is noted that the thigh meat had higher thiobarbituric acid reactive substances values than the breast in all chicken breeds. Though Woorimatdak showed higher antioxidant enzyme activity and lower released-iron percentage among Korean native chickens, no differences were found on lipid oxidation. We confirm that the dark meat of poultry exhibited higher antioxidant enzyme activity and contained more iron than the white meat.

Effect of acid whey and freeze-dried cranberries on lipid oxidation and fatty acid composition of nitrite-/nitrate-free fermented sausage made from deer meat

Objective

This study evaluated the effect of acid whey and freeze-dried cranberries on the physicochemical characteristics, lipid oxidation and fatty acid composition of nitrite-free fermented sausage made from deer meat and pork fat. Antioxidant interactions between acid whey and cranberry compounds were also explored.

Methods

Four formulations of fermented venison sausage were prepared: F1 (control), F2 (with 5% liquid acid whey), F3 (with 0.06% of freeze-dried cranberries), and F4 (with 5% liquid acid whey and 0.06% of freeze-dried cranberries). Each sample was analyzed for pH, water activity (a_w), heme iron content, 2-thiobarbituric acid reactive substances (TBARS) value and conjugated dienes at the end of the manufacturing process and at 30 and 90 days of refrigerated storage. Fatty acid composition was measured once at the end of the manufacturing process.

Results

At the end of ripening, all samples presented statistically different values for a pH range of 4.47 to pH 4.59. The sum of the unsaturated fatty acids was higher, while the conjugated diene and the TBARS values were lower in sausages with freeze-dried cranberries as compared to the control sausage. The highest content of heme iron (21.52 mg/kg) at day 90 was found in the sausage formulation with the addition of freeze-dried cranberries, which suggests that the addition of cranberries stabilized the porphyrin ring of the heme molecule during storage and thereby reduced the release of iron. The use of liquid acid whey in combination with cranberries appears to not be justified in view of the oxidative stability of the obtained products.

Conclusion

The results suggest that the application of freeze-dried cranberries can lower the intensity of oxidative changes during the storage of nitrite-free fermented sausage made from deer meat.

Beneficial Effects of Traditional Seasonings on Quality Characteristics of Fermented Sausages

Though traditional seasonings are widely used in many dishes, however, no attention has been paid to the investigation of their effects on quality characteristics of food products. The present investigation was undertaken to study the effects of incorporating several traditional seasonings including doenjang (fermented soybean paste), gochu-jang (red pepper paste), fresh medium-hot, and hot peppers, and fresh garlic on the lipid oxidation, cholesterol content and sensory characteristics of fermented sausages. Six fermented sausage treatments (5 with 1% (w/w) each test seasoning and 1 without added test seasoning (control) were prepared. The addition of seasonings generally had beneficial effects on the improvement of fermented sausage's quality however the effects differed depending on the each type of seasonings added. Significant lower pH values were found in all fermented sausages made with the seasonings while, lower levels of lipid oxidation were found in the treatments with hot peppers and garlic as compared with the control (p<0.05). The treatment with seasonings did not cause color or texture defects in the products whereas the sausages made with gochu-jang had significantly higher Commission International de l'Eclairagea* (redness) value in comparison with the control. Noticeably, incorporating doenjang, medium-hot peppers, hot peppers and garlic resulted in reduction of 26.50, 32.54, 47.04, and 48.54 mg cholesterol/100 g samples, respectively (p<0.05). Higher scores for the sensory traits such as aroma, taste, color and acceptability were also given for the sausages made with seasonings. The current work demonstrates that the test seasonings represent potentially natural ingredients to be used for producing healthier fermented sausages.

Ethanol Extracts from Mistletoe (Viscum album L.) Act as Natural Antioxidants and Antimicrobial Agents in Uncooked Pork Patties during Refrigerated Storage

The antioxidant potential of mistletoe (Viscum album L. var. coloratum Ohwi; VAL) extract in uncooked pork patties was evaluated. Three concentrations of VAL extract (0.1 [T1], 0.5% [T2] and 1.0% [T3]) along with 0.02% ascorbic acid as a positive control (V) were added to ground pork and pork patties were prepared. Incorporation of VAL extract decreased (p<0.05) the pH of the pork patties throughout the storage time and reduced (p<0.01) the thiobarbituric acid reactive substance values after day 14 of storage. Total plate counts of the VAL extract-treated samples and V-treated samples were also significantly lower (p<0.01) than that of the control (C) throughout the storage period. In addition, odor scores of the VAL extract-treated patties were lower than those of the C- or V-treated samples on 3rd day of the storage period. These results demonstrated that the VAL extract acts as a natural antioxidant in uncooked pork products.

Effect of Various Phyto-extracts on Physico-chemical, Colour, and Oxidative Stability of Pork Frankfurters

Lipid oxidation, colour stability and physico-chemical quality of pork frankfurters with the incorporation of 0.30% sea buckthorn (SBT), 0.10% grape seed (GSE), 0.03% green tea (GTE), 0.12% fenugreek seed (FSE) and 0.10% Acacia catechu (ACE) were studied during 20 days of refrigerated aerobic storage. The SBT and ACE were identified as being the most effective antioxidants to retard lipid oxidation with the potency decreasing in the following order: SBT>ACE>GSE>GTE>FSE based on thiobarbituric acid reacting substances, peroxide value and free fatty acids. In all samples pH and a_w decreased during storage period. The L* value of treated as well as control samples decreased over time while SBT and ACE exhibited an increased redness producing higher a* values than other treatments. However, GTE was more effective in increasing b* values than other treatments at the end of storage. The results suggest that functional plant-derived extracts can be valuable to the modification of frankfurter formulations for improved oxidative stability as well as quality characteristics.

15-Hydroxyprostaglandin dehydrogenase generation of electrophilic lipid signaling mediators from hydroxy ω-3 fatty acids

15-Hydroxyprostaglandin dehydrogenase (15PGDH) is the primary enzyme catalyzing the conversion of hydroxylated arachidonic acid species to their corresponding oxidized metabolites. The oxidation of hydroxylated fatty acids, such as the conversion of prostaglandin (PG) E2 to 15-ketoPGE2, by 15PGDH is viewed to inactivate signaling responses. In contrast, the typically electrophilic products can also induce anti-inflammatory and anti-proliferative responses. This study determined that hydroxylated docosahexaenoic acid metabolites (HDoHEs) are substrates for 15PGDH. Examination of 15PGDH substrate specificity was conducted in cell culture (A549 and primary human airway epithelia and alveolar macrophages) using chemical inhibition and shRNA knockdown of 15PGDH. Substrate specificity is broad and relies on the carbon position of the acyl chain hydroxyl group. 14-HDoHE was determined to be the optimal DHA substrate for 15PGDH, resulting in the formation of its electrophilic metabolite, 14-oxoDHA. Consistent with this, 14-HDoHE was detected in bronchoalveolar lavage cells of mild to moderate asthmatics, and the exogenous addition of 14-oxoDHA to primary alveolar macrophages inhibited LPS-induced proinflammatory cytokine mRNA expression. These data reveal that 15PGDH-derived DHA metabolites are biologically active and can contribute to the salutary signaling actions of Ω-3 fatty acids.

Effect of cattle breed on meat quality, muscle fiber characteristics, lipid oxidation and Fatty acids in china

The objective was to compare meat quality, muscle fiber characteristics, lipid oxidation and fatty acids of Limousin (LIM), Simmtental (SIM), Luxi (LX), Qinchuan (QC) and Jinnan (JN) offered the same diet in China. After finishing, eight bulls from each breed were randomly selected for slaughter at 18.5 months old. Longissimus dorsi (ld) muscle was taken from the carcass for meat quality evaluations. Breed had little effect on most of meat and fat color parameters except for Hue and b* in which QC had lower values. LIM showed higher pH (24 h) and better water holding capacity than other breeds. LIM showed the lowest dry matter content but the highest crude protein. LX and LIM had higher percentage and density of red muscle fiber than other breeds. Lipid oxidations were significantly lower in LIM than in QC, with the LX, SIM and JN having the intermediate values. Compared to other four breeds, QC provided the highest values of polyunsaturated fatty acids (PUFA), n-6 fatty acids and n-3 fatty acids. In conclusion, LIM scored better on most of meat quality characteristics; however, local breeds such as LX and QC also had better muscle fiber characteristics and better fatty acids composition.

Flavour chemistry of chicken meat: a review

Flavour comprises mainly of taste and aroma and is involved in consumers’ meat-buying behavior and preferences. Chicken meat flavour is supposed to be affected by a number of ante- and post-mortem factors, including breed, diet, post-mortem ageing, method of cooking, etc. Additionally, chicken meat is more susceptible to quality deterioration mainly due to lipid oxidation with resulting off-flavours. Therefore, the intent of this paper is to highlight the mechanisms and chemical compounds responsible for chicken meat flavour and off-flavour development to help producers in producing the most flavourful and consistent product possible. Chicken meat flavour is thermally derived and the Maillard reaction, thermal degradation of lipids, and interaction between these 2 reactions are mainly responsible for the generation of flavour and aroma compounds. The reaction of cysteine and sugar can lead to characteristic meat flavour specially for chicken and pork. Volatile compounds including 2-methyl-3-furanthiol, 2-furfurylthiol, methionol, 2,4,5-trimethyl-thiazole, nonanol, 2-trans-nonenal, and other compounds have been identified as important for the flavour of chicken. However 2-methyl-3-furanthiol is considered as the most vital chemical compound for chicken flavour development. In addition, a large number of heterocyclic compounds are formed when higher temperature and low moisture conditions are used during certain cooking methods of chicken meat such as roasting, grilling, frying or pressure cooking compared to boiled chicken meat. Major volatile compounds responsible for fried chicken are 3,5-dimethyl-1,2,4-trithiolanes, 2,4,6-trimethylperhydro-1,3,5-dithiazines, 3,5-diisobutyl-1,2,4-trithiolane, 3-methyl-5-butyl-1,2,4-trithiolane, 3-methyl-5-pentyl-1,2,4-trithiolane, 2,4-decadienal and trans-4,5-epoxy-trans-2-decenal. Alkylpyrazines were reported in the flavours of fried chicken and roasted chicken but not in chicken broth. The main reason for flavour deterioration and formation of undesirable “warmed over flavour” in chicken meat products are supposed to be the lack of α-tocopherol in chicken meat.

Oxidation of endogenous N-arachidonoylserotonin by human cytochrome P450 2U1

Cytochrome P450 (P450) 2U1 has been shown to be expressed, at the mRNA level, in human thymus, brain, and several other tissues. Recombinant P450 2U1 was purified and used as a reagent in a metabolomic search for substrates in bovine brain. In addition to fatty acid oxidation reactions, an oxidation of endogenous N-arachidonoylserotonin was characterized. Subsequent NMR and mass spectrometry and chemical synthesis showed that the main product was the result of C-2 oxidation of the indole ring, in contrast to other human P450s that generated different products. N-Arachidonoylserotonin, first synthesized chemically and described as an inhibitor of fatty acid amide hydrolase, had previously been found in porcine and mouse intestine; we demonstrated its presence in bovine and human brain samples. The product (2-oxo) was 4-fold less active than N-arachidonoylserotonin in inhibiting fatty acid amide hydrolase. The rate of oxidation of N-arachidonoylserotonin was similar to that of arachidonic acid, one of the previously identified fatty acid substrates of P450 2U1. The demonstration of the oxidation of N-arachidonoylserotonin by P450 2U1 suggests a possible role in human brain and possibly other sites.

Effect of mechanically deboned chicken meat hydrolysates on the physicochemical properties of imitation fish paste

This study investigated on the effects of adding mechanically deboned chicken meat (MDCM) hydrolysates on the quality properties of imitation fish paste (IFP) during storage. IFP was prepared from Alaska Pollack, spent laying hens surimi and protein hydrolysates which were enzymatically extracted from MDCM. The study was designed as a 3×4 factorial design with three MDCM hydrolysate content groups (0%, 0.4%, and 0.8%) and four storage times (0, 2, 4, and 6 weeks). Addition of MDCM hydrolysates increased crude fat content but lowered water content (p<0.05). The breaking force of IFP, an indicator of gel formation, increased in treated groups compared to control (p<0.05). Angiotensin I-converting enzyme (ACE) activity was inhibited and free radical scavenging activity increased with increasing MDCM hydrolysate content (p<0.05). In conclusion, the addition of MDCM to IFP improves gel characteristics. Additionally, protein hydrolysates from MDCM serve as a potential source of ACE inhibiting peptides.

Whole-body substrate metabolism is associated with disease severity in patients with non-alcoholic fatty liver disease

OBJECTIVES

In non-alcoholic fatty liver disease (NAFLD), hepatic steatosis is intricately linked with a number of metabolic alterations. We studied substrate utilisation in NAFLD during basal, insulin-stimulated and exercise conditions, and correlated these outcomes with disease severity.

METHODS

20 patients with NAFLD (mean ± SD body mass index (BMI) 34.1 ± 6.7 kg/m(2)) and 15 healthy controls (BMI 23.4 ± 2.7 kg/m(2)) were assessed. Respiratory quotient (RQ), whole-body fat (Fat ox) and carbohydrate (CHO ox) oxidation rates were determined by indirect calorimetry in three conditions: basal (resting and fasted), insulin-stimulated (hyperinsulinaemic-euglycaemic clamp) and exercise (cycling at an intensity to elicit maximal Fat ox). Severity of disease and steatosis were determined by liver histology, hepatic Fat ox from plasma β-hydroxybutyrate concentrations, aerobic fitness expressed as VO2 peak, and visceral adipose tissue (VAT) measured by computed tomography.

RESULTS

Within the overweight/obese NAFLD cohort, basal RQ correlated positively with steatosis (r=0.57, p=0.01) and was higher (indicating smaller contribution of Fat ox to energy expenditure) in patients with NAFLD activity score (NAS) ≥ 5 vs <5 (p=0.008). Both results were independent of VAT, % body fat and BMI. Compared with the lean control group, patients with NAFLD had lower basal whole-body Fat ox (1.2 ± 0.3 vs 1.5 ± 0.4 mg/kg FFM/min, p=0.024) and lower basal hepatic Fat ox (ie, β-hydroxybutyrate, p=0.004). During exercise, they achieved lower maximal Fat ox (2.5 ± 1.4 vs. 5.8 ± 3.7 mg/kg FFM/min, p=0.002) and lower VO2 peak (p<0.001) than controls. Fat ox during exercise was not associated with disease severity (p=0.79).

CONCLUSIONS

Overweight/obese patients with NAFLD had reduced hepatic Fat ox and reduced whole-body Fat ox under basal and exercise conditions. There was an inverse relationship between ability to oxidise fat in basal conditions and histological features of NAFLD including severity of steatosis and NAS.

Isolation and characterization of two geometric allene oxide isomers synthesized from 9S-hydroperoxylinoleic acid by cytochrome P450 CYP74C3: stereochemical assignment of natural fatty acid allene oxides

Specialized cytochromes P450 or catalase-related hemoproteins transform fatty acid hydroperoxides to allene oxides, highly reactive epoxides leading to cyclopentenones and other products. The stereochemistry of the natural allene oxides is incompletely defined, as are the structural features required for their cyclization. We investigated the transformation of 9S-hydroperoxylinoleic acid with the allene oxide synthase CYP74C3, a reported reaction that unexpectedly produces an allene oxide-derived cyclopentenone. Using biphasic reaction conditions at 0 °C, we isolated the initial products and separated two allene oxide isomers by HPLC at -15 °C. One matched previously described allene oxides in its UV spectrum (λmax 236 nm) and NMR spectrum (defining a 9,10-epoxy-octadec-10,12Z-dienoate). The second was a novel stereoisomer (UV λmax 239 nm) with distinctive NMR chemical shifts. Comparison of NOE interactions of the epoxy proton at C9 in the two allene oxides (and the equivalent NOE experiment in 12,13-epoxy allene oxides) allowed assignment at the isomeric C10 epoxy-ene carbon as Z in the new isomer and the E configuration in all previously characterized allene oxides. The novel 10Z isomer spontaneously formed a cis-cyclopentenone at room temperature in hexane. These results explain the origin of the cyclopentenone, provide insights into the mechanisms of allene oxide cyclization, and define the double bond geometry in naturally occurring allene oxides.

Effects of Electrical Stimulation on Lipid Oxidation and Warmed-over Flavor of Precooked Roast Beef

Many manufacturing processes damage the structure of meat products and this often contributes to lipid oxidation which could influence warmed-over flavor (WOF) in precooked beef that is reheated beef. Electrical stimulation causes contraction of muscles and improves tissue tenderization. The purpose of this study was to evaluate the rate of lipid oxidation or warmed-over flavor that could be affected by electrical stimulation of precooked roast beef after refrigerated storage and reheating. The results show that there was no significant difference between chemical compositions and cooking yields when comparing non-electrically stimulated and electrically stimulated roast beef. Moreover, electrical stimulation had no significant effect on oxidative stability and off-flavor problems of precooked roast beef as evaluated by thiobarbituric acid reactive substances (TBARS) and sensory test (warmed-over aroma and warmed-over flavor). However, there was an increased undesirable WOF and a decrease in tenderness for both ES and Non-ES treatments over refrigerated storage time. Electrical stimulation did cause reactions of amino acids or other compounds to decrease the desirable beef flavor in re-cooked meat.