Mirko Betti

Omega-3-enriched broiler meat: 3. Fatty acid distribution between triacylglycerol and phospholipid classes

Consumers are becoming more aware of the effect of the food they eat on their health. One of the ways they hope to reduce their risk of cardiovascular disease is by consuming more foods enriched with n-3 polyunsaturated fatty acids (PUFA). Due to the high content of alpha-linolenic acid (LNA), dietary flaxseed is a good source for increasing n-3 PUFA in poultry meat. A study was conducted with 2 primary objectives: to establish the distribution of n-3 PUFA between triacylglycerol (TAG) and phospholipid of broiler chicken breast and thigh meat and to determine the duration of dietary flaxseed supplementation required to ensure a level of n-3 PUFA of 300 mg per 100 g of meat necessary to label meat as a source of n-3 PUFA. This experiment was conducted as a 2 x 8 factorial, with 2 dietary levels of ground flaxseed (10 and 17%) and 8 durations of dietary flaxseed before processing [0 (control), 4, 8, 12, 16, 20, 24, and 35 d]. A total of 128 Ross x Ross 308 mixed-sex broilers were evaluated to 35 d of age. Breast and thigh meat fatty acid composition was analyzed on duplicate samples of ground meat pooled from 8 birds per treatment. Broken-stick analysis was used to estimate the duration required to achieve 300 mg of n-3 PUFA per 100 g of breast meat. Results clearly indicated that LNA was mainly deposited in the TAG fraction of both breast and thigh meat. Enriching the chicken breast meat with 300 mg of n-3 PUFA per 100 g of meat was achieved in 11.3 and 26.2 d with a 17 and 10% level of flaxseed in diet, respectively. Although a significant increase of n-3 long-chain PUFA (20:5n-3, 22:5n-3, and 22:6n-3) was found in the phospholipid and TAG fraction of both tissues, the concentration of these functional components was low. More than 95% of n-3 PUFA enrichment was due to LNA.

Omega-3-enriched broiler meat: 2. Functional properties, oxidative stability, and consumer acceptance

Consumers are becoming more aware of the impact on their health of the food they eat. One of the ways they hope to reduce their risk of cardiovascular disease is by consuming more foods enriched with polyunsaturated fatty acids (PUFA), particularly n-3 fatty acids. Flaxseed is a good source for increasing the n-3 PUFA in poultry meat because of the high content of alpha-linolenic acid. A study was conducted to identify an optimal process to enrich of broiler diets with n-3 PUFA by using 2 levels of flaxseed fed for various times before processing. The acceptability of broiler meat functional properties was tested to ensure that further processing efficiencies would not be compromised by the enrichment strategy. This experiment was conducted as a 2 x 8 factorial, with 2 dietary levels of ground flaxseed (10 and 17%) fed for 8 lengths of time before processing [0 (control), 4, 8, 12, 16, 20, 24, and 35 d]. Of 650 Ross x Ross 308 mixed-sex broilers reared in this study, 128 were used to evaluate breast and thigh meat functional properties, oxidative stability, and sensory analysis. No statistical interactions were found between treatments for chicken breast meat quality traits. The duration of feeding flaxseed strongly affected meat quality parameters. In particular, feeding flaxseed for 16 d resulted in a final pH of 5.65, compared with 5.93 in the control. The lower ultimate pH found in animals fed flaxseed affected meat cooking loss, drip loss, and shear value (P < 0.0001). Shear value significantly increased after 16 d of feeding flaxseed (P < 0.0001). Susceptibility to oxidation increased in both breast and thigh broiler meat with the duration of feeding flaxseed. Enriching the diet for less than 16 d did not result in perceivable sensory defects. Duration of flaxseed feeding significantly affected the color characteristics, functional properties, and oxidative stability of broiler meat.

Omega-3-enriched broiler meat: 1. Optimization of a production system

Consumer awareness of the health benefits of n-3 fatty acids is growing and is driving consumer demand for enriched food products. Enrichment of meat with n-3 fatty acids is an opportunity for the broiler production sector to add value to their product, but enrichment can increase the cost of production. A study was conducted to determine an optimal production strategy for n-3 enrichment of broiler meat using ground full-fat flaxseed. Low and high levels of dietary flaxseed (10 and 17%, respectively) were fed to broilers for 8 lengths of time (0, 4, 8, 12, 16, 20, 24, or 35 d) before processing at 35 d. Increasing the level or duration decreased feed intake, BW, and the percentage yield of carcass and breast. Flaxseed level and duration of feeding increased feed conversion ratios and the cost of production. Feeding flaxseed at 10 and 17% increased breast n-3 fatty acid levels by 7.65 and 13.70 mg/100 g of meat per day, respectively. In breast meat, the threshold level of 300 mg/g, required in Canada for labeling foods as a source of n-3 fatty acids, was reached at 12.1 and 24.1 d in the high and low flaxseed treatments, respectively. This was due primarily to a tripling of alpha-linolenic acid (18:3n-3) levels in the breast meat. Levels of the long-chain n-3 fatty acid eicosapentaenoic acid increased significantly in the breast meat with increased level and duration of flax feeding, indicating that birds were able to desaturate and elongate alpha-linolenic acid to eicosapentaenoic acid. To minimize cost, while achieving adequate breast meat n-3 enrichment, carcass weight, and meat yield, feeding 10% flaxseed for 24.1 d before processing is recommended as an optimal breast meat n-3 enrichment strategy. The optimal thigh meat n-3 enrichment strategy was to feed 10% flaxseed for 4.54 d before processing.

Studies on the Formation of Maillard and Caramelization Products from Glucosamine Incubated at 37 °C

This experiment compared the in vitro degradation of glucosamine (GlcN), N-acetylglucosamine, and glucose in the presence of NH3 incubated at 37 °C in phosphate buffer from 0.5 to 12 days. The reactions were monitored with UV-vis absorption and fluorescence emission spectroscopies, and the main products of degradation, quinoxaline derivatives of α-dicarbonyl compounds and condensation products, were determined using UHPLC-UV and Orbitrap mass spectrometry. GlcN produced two major dicarbonyl compounds, glucosone and 3-deoxyglucosone, ranging from 709 to 3245 mg/kg GlcN and from 272 to 4535 mg/kg GlcN, respectively. 3,4-Dideoxyglucosone-3-ene, glyoxal, hydroxypyruvaldehyde, methylglyoxal, and diacetyl were also detected in lower amounts compared to glucosone and 3-deoxyglucosone. Several pyrazine condensation products resulting from the reaction between dicarbonyls and GlcN were also identified. This study determined that GlcN is a significantly unstable molecule producing a high level of degradation products at 37 °C.

Glycation and transglutaminase mediated glycosylation of fish gelatin peptides with glucosamine enhance bioactivity

A mixture of novel glycopeptides from glycosylation between cold water fish skin gelatin hydrolysates and glucosamine (GlcN) via transglutaminase (TGase), as well as glycation between fish gelatin hydrolysate and GlcN were identified by their pattern of molecular distribution using MALDI-TOF-MS. Glycated/glycosylated hydrolysates showed superior bioactivity to their original hydrolysates. Alcalase-derived fish skin gelatin hydrolysate glycosylated with GlcN in the presence of TGase at 25°C (FAT25) possessed antioxidant activity when tested in a linoleic acid oxidation system, when measured according to its 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and when tested at the cellular level with human hepatocarcinoma (HepG2) cells as target cells. In addition, Alcalase-derived glycosylated hydrolysates showed specificity toward the inhibition of Escherichia coli (E. coli). The Flavourzyme-derived glycopeptides prepared at 37°C (FFC37 and FFT37) showed better DPPH scavenging activity than their native hydrolysates. The glycated Flavourzyme-derived hydrolysates were found to act as potential antimicrobial agents when incubated with E. coli and Bacillus subtilis.

The use of β-glucan as a partial salt replacer in high pressure processed chicken breast meat.

The effect of various ingredients such as sodium chloride (NaCl), sodium tripolyphosphate (STPP) and β-glucan (BG) on the biochemical properties of chicken breast proteins during temperature assisted high pressure processing was studied. Total protein solubility revealed that 600MPa pressure and 40(o)C are critical for the denaturation of proteins in STPP samples. Increase in reactive sulfhydryl groups with pressure indicate the exposure of buried sulfhydryl groups. Hydrophobicity and sulfhydryl contents revealed that hydrophobic interaction and disulphide bond formation are responsible for gel formation. The study revealed that 40(o)C and 400/600MPa pressure is optimum for high pressure processing of chicken breast meat. Addition of β-glucan with reduced NaCl and in the absence of sodium tripolyphosphate could produce gels with similar properties to those with 2.5% NaCl addition. Hence it is proposed that β-glucan can be used to reduce NaCl content of chicken products produced by temperature assisted high pressure processing.

Effect of holding temperature, shackling, sex, and age on broiler breast meat quality

Antemortem holding temperature and flapping can affect broiler pectoralis major (referred to as p. major) meat quality. The influence of environmental temperature 12 to 14 h before processing and antemortem handling on p. major functional properties and color was tested at multiple processing ages in a 3 × 2 × 5 factorial design study. At 28, 35, 42, 49, and 56 d of age, mixed-sex broilers were crated and held in one of 3 target temperature treatments: heat (30°C), thermoneutral (21°C), or cool (7°C). Following feed withdrawal, birds were transported to a processing facility where either a long (120 s) or short (<10 s) shackling treatment was imposed. Sex was determined at processing. Lightness, redness, and yellowness values were measured at deboning [4.50 to 8.25 h postmortem (PM)] and at 24 h PM. Ultimate pH was measured at 24 h PM. Drip loss, cook loss, and Allo-Kramer shear force were determined at 72 h PM. Ultimate pH was highest in the cool treatment, with no difference between heat and thermoneutral treatments (5.97 vs. 5.87 and 5.90, respectively; P = 0.0004). Ultimate pH correlated negatively with drip loss (r = -0.47; P < 0.0001). Drip loss was lowest in the cool treatment, with no difference between the heat and thermoneutral treatments (2.06 vs. 2.24 and 2.19%, respectively; P = 0.007). The p. major from broilers in the heat treatment had higher Allo-Kramer shear force values than those in both the thermoneutral and cool treatments (4.64 kg/g vs. 4.21 and 4.21 kg/g, respectively; P = 0.023). With the exception of 49 d, broilers subjected to the long shackling treatment had higher redness values at deboning than broilers subjected to the short shackling treatment; by 24 h PM only the 28-d broilers subjected to the long shackling treatment had higher redness values. Higher hue angles at deboning and 24 h PM were observed in the short treatment compared with the long treatment (65.58 vs. 57.46 and 68.48 vs. 63.31, respectively; P < 0.0001), indicating that p. major from long-shackled broilers were redder in appearance. Ultimate pH was lower in female broilers than in male broilers (5.87 vs. 5.96, respectively; P < 0.0001) and subsequent drip loss was higher in females compared with males (2.34 vs. 1.99%, respectively; P < 0.0001). Although temperature and handling before slaughter affected p. major color and texture traits, the differences may not be large enough to have commercial significance. Differences in p. major quality attributable to sex of the bird may have greater commercial significance than previously reported.

Functional and rheological properties of proteins in frozen turkey breast meat with different ultimate pH

Functional and rheological properties of proteins from frozen turkey breast meat with different ultimate pH at 24 h postmortem (pH(24)) have been studied. Sixteen breast fillets from Hybrid Tom turkeys were initially selected based on lightness (L*) values for each color group (pale, normal, and dark), with a total of 48 breast fillets. Further selection of 8 breast samples was made within each class of meat according to the pH(24). The average L* and pH values of the samples were within the following range: pale (L* >52; pH ≤5.7), normal (46 < L* < 52; 5.9 < pH <6.1), and dark (L* <46; pH ≥6.3), referred to as low, normal, and high pH meat, respectively. Ultimate pH did not cause major changes in the emulsifying and foaming properties of the extracted sarcoplasmic and myofibrillar proteins. An SDS-PAGE profile of proteins from low and normal pH meat was similar, which revealed that the extent of protein denaturation was the same. Low pH meat had the lowest water-holding capacity compared with normal and high pH meat as shown by the increase in cooking loss, which can be explained by factors other than protein denaturation. Gel strength analysis and folding test revealed that gel-forming ability was better for high pH meat compared with low and normal pH meat.Dynamic viscoelastic behavior showed that myosin denaturation temperature was independent of pH(24). Normal and high pH meat had similar hardness, springiness, and chewiness values as revealed by texture profile analysis. The results from this study indicate that high pH meat had similar or better functional properties than normal pH meat. Therefore, high pH meat is suitable for further processed products, whereas low pH meat may need additional treatment or ingredient formulations to improve its functionality.

Chemical, rheological and surface morphologic characterisation of spent hen proteins extracted by pH-shift processing with or without the presence of cryoprotectants

The chemical and rheological properties of spent hen proteins recovered by acid and alkaline extraction have been studied with/without cryoprotectants (CP) after 3 weeks of frozen storage. Four pH values (2.0, 2.5, 11.5, and 12.0) were used for extraction. CP addition prevented freeze-induced denaturation and oxidation in all extracted proteins, as revealed by significant increases in reactive sulphydryl groups (p<0.0001), and a decrease in the formation of carbonyl groups (p<0.0001). The alkaline extracted proteins with CP formed more viscoelastic gels compared to the others, while samples without CP failed to form a gel network. FTIR of the protein isolates with CP showed a protective effect on the secondary structure of the isolated proteins. Scanning electron micrographs showed a protective shield of CP around the isolated proteins.

Extraction, Isolation and Analysis of Chondroitin Sulfate Glycosaminoglycans

Glycosaminoglycans (GAGs) including chondroitin sulfate (CS) and chondroitin sulfate/dermatan sulfate (CS/DS) copolymers are anionic straight chain polysaccharides. They are galactosamine containing GAGs (galactosaminoglycans) having wide range of applications in pharmaceutical, cosmetic and food industries. This article reviews techniques to isolate and characterize these galactosaminoglycans from animal and poultry tissues. Patent based information is also discussed. Cartilaginous tissues are the major source of CS consisting entirely of D-glucuronosyl-N-acetylgalactosamine repeating disaccharide units, in which the galactosamine is sulfated at C4 or C6. In contrast, most galactosaminoglycans in non-cartilaginous connective tissues (e.g. skin and tendon) are CS/DS copolymers comprised of varying proportions of D-glucuronosyl-N-acetylgalactosamine and L-iduronosyl-N-acetylgalactosamine. Tissues are digested with proteinase (e.g. papain) to liberate GAGs, which are fractionated to isolate and purify galactosaminoglycans. Common techniques used for fractionation of GAGs include: precipitation with different concentrations of ethanol; solubilization of GAG precipitated as GAG-quarternary ammonium compound complexes with different concentrations of NaCl; anion exchange chromatography and gel filtration chromatography. Purified galactosaminoglycans are examined by various methods including chondroitinase digestion, high performance liquid chromatography and electrophoresis. Histological methods are used to localize galactosaminoglycans in tissues. The patent information on the CS hydrolase and ultraviolet irradiation may be useful for the preparation of CS oligosaccharide.