Addition of fermented and unfermented grape skin in broilers' diets: effect on digestion, growth performance, intestinal microbiota and oxidative stability of meat.

Grape skin is a source of polyphenols with antioxidant and antimicrobial properties. Little information is available regarding its application in animal feeding. The present study investigated the effect of inclusion of fermented (FS) and unfermented (UFS) grape skin at two different doses (30 g/kg, FS30 and UFS30, and 60 g/kg, FS60 and UFS60) and 200 mg/kg vitamin E (α-tocopheryl acetate) in a corn-soybean diet on growth performance, ileal protein digestibility, ileal and excreta total extractable polyphenols content and digestibility, intestinal microbiota and thigh meat oxidation in broiler chickens. Growth performance was depressed in chickens fed UFS and FS diets. A reduction in ileal protein digestibility was also observed in birds fed UFS, being this effect more pronounced in those fed 60 g/kg. The dietary inclusion of grape skin increased both ileal and excreta polyphenols contents, being higher in birds fed UFS than in those fed FS. Excreta moisture content increased in birds fed UFS and FS diets. No effect of dietary inclusion of grape skin was observed on ileal counts of lactic-acid bacteria and Clostridium, but UFS inclusion in the diet reduced ileal count of Escherichia coli as compared with FS dietary inclusion. After 7 days of refrigerated storage, values of thiobarbituric acid reactive substances (TBARS) were lower in chicken meat when grape skin was added in the diet at 60 g/kg instead of 30 g/kg, and meat from birds fed 60 g/kg of grape skin reached TBARS values similar to those of birds supplemented with vitamin E. In conclusion, high doses of grape skin polyphenols depressed growth performance and protein digestibility, and increased excreta moisture content. Unfermented grape skin contained more polyphenols than FS, and its inclusion in the diet led to higher ileal and excreta polyphenols contents and to a lower ileal count of E. coli. Furthermore, the antioxidant potential of the polyphenols present in grape skin was observed after 7 days of meat storage, with the dose of 60 g/kg of grape skin being as effective as vitamin E supplementation in maintaining oxidative stability of meat.

Chia and oat emulsion gels as new animal fat replacers and healthy bioactive sources in fresh sausage formulation.

This paper examines the effect of emulsion gels (EG) prepared with chia (CEG) and oats (OEG) used as animal fat replacers in reduced-fat fresh sausages (longaniza) (LRF) during chilled storage. Reduced-fat samples were reformulated with CEG and OEG, (LRF/CEG and LRF/OEG respectively). Normal (LNF/P) and reduced-fat (LRF/P) (all-pork-fat) sausages were used as controls. Nutritional composition and microbiological, technological and sensory characteristics of sausages were evaluated. The presence of an EG affected (P<0.05) the concentrations of some minerals and amino acids in sausages. CEG improved MUFA and PUFA contents. Cooking loss was lower (P<0.05) in LRF/CEG and LRF/OEG than in the controls. Of all the reduced-fat samples, Kramer shear force values (KSF) were highest (P<0.05) in the ones containing an EG. KSF generally increased (P<0.05) over storage in all samples. The microbial count was significantly affected by the use of CEG. Sensory properties were affected by the incorporation of an EG, but all sausages were judged acceptable.

Free-sodium salts mixture and AlgySalt® use as NaCl substitutes in fresh and cooked meat products intended for the hypertensive population.

This work aims at reducing the use of added NaCl in processed meat products because of its negative effects on hypertensive population by replacing it by sodium-free salts mixture (SM: KCl, MgCl2 and CaCl2) in fresh and cooked sausages. The technological, sensory, and microbiological effects of SM were compared with a commercial replacer based on seaweed extracts (AlgySalt®). A total substitution of NaCl with the latter and a partial one with SM (80% and 50%) were studied in cooked sausages and a total NaCl substitution with both substitutes was performed in fresh sausages. As a result, hardness increased in AlgySalt® reformulated samples, while it decreased when 80% SM were used. Whereas, AlgySalt® induced less cooking loses than SM. To some extent, microbiological counts showed a similarity between reformulated and control samples for both sausage types, whereas reformulated products containing SM revealed better sensory properties for both meat products. Therefore, using SM as NaCl replacer is adequate for processed meat products.

Infrared spectroscopy used to determine effects of chia and olive oil incorporation strategies on lipid structure of reduced-fat frankfurters.

This article reports an infrared spectroscopic study, using attenuated total reflectance (ATR-FTIR), on the structural characteristics of lipids in frankfurters as affected by different strategies to replace animal fat with chia flour and olive oil. Three incorporation strategies were considered: direct addition (FCO) and addition in a conventional emulsion (non-gelled) (FCE) or an emulsion gel using alginate as a gelling agent (FCEG). Reduced-fat (all-pork-fat) frankfurters (FP) were used as reference. Proximate composition and specific technological properties (pH, processing loss, texture) were also evaluated. FCE and FCEG frankfurters showed a shift to higher frequencies and the highest (p<0.05) half-bandwidth in the νasCH2 and νsCH2 bands. These spectroscopic results could be related to the fact that the lipid chain was more disorderly in these samples, presumably because there were more lipid interactions than in the reference frankfurter. These features of lipid structure correlated significantly with processing loss and textural behaviour.

Strategies for incorporation of chia (Salvia hispanica L.) in frankfurters as a health-promoting ingredient.

Different strategies were examined for incorporation of chia flour (10%) and olive oil to improve the fat content in frankfurters. Nutritional composition, technological properties, sensory and microbiological analyses were studied as affected by the strategy used and by chilling storage. Chia increased total dietary fibre (98% insoluble dietary fibre) and minerals (K, Mg, Ca, Mn) irrespective of the incorporation strategy. Fat and energy content reduction (>26%) were achieved in all frankfurters reformulated with chia and olive oil. Chia addition increased linolenic acid and reduced processing and purge in all samples. Lightness and redness of frankfurters were affected by the presence of chia, but there was no clear evidence of influence by the mode of addition. Frankfurter texture was influenced by the strategy used to incorporate chia and olive oil and by chilling storage. Samples were judged acceptable and contained low microorganism levels. Frankfurters containing chia were suitable for labelling with certain nutrition and health claims.

Emulsion gels as potential fat replacers delivering ß-glucan and healthy lipid content for food applications.

Oat emulsion gels and oil-free oat gels were formulated with varying proportions of oat bran/olive oil (from 12/40 to 28/0) without or with alginate or gelatin used as animal fat replacers and/or to provide ß-glucan and MUFA for meat products. Composition, technological properties (thermal stability, colour, texture, etc.) and the effects of chilled and frozen storage of samples were evaluated. Depending on the proportion, samples developed for use as animal fat replacers in meat products may endow these with properties qualifying them for nutrition and health claims. No samples showed any noticeable syneresis and all showed good thermal stability. Increasing of oat bran/olive oil increased a* and reduced b* values, while differences in L* depended on the gelling agent. Penetration force (PF) and gel strength increased when the oat bran/oil ratio increased, with the highest values in the samples containing alginate or gelatin. Thermal losses and PF generally increased during chilled and frozen storage, and no significant differences were observed in colour or pH over storage.

Properties of reformulated hot dog sausage without added nitrites during chilled storage.

The aim of this study was to assess the effect of a complete nitrite replacement strategy using celery, carmine, sodium lactate and orange dietary fibre combined with vitamins C and E, on the quality characteristics (technological, sensorial and safety properties) of hot dog sausages (five samples) during chilled storage (2 ± 1℃ 60 days). Nitrite replacers (combined with vitamins C and E) presented antioxidant activity, reducing lipid oxidation in reformulated samples. At the end of storage redness (a*) was similar in the control sample (with added nitrite) and in the sample without added nitrite. Sensory evaluation detected no significant difference between samples with and without added nitrite. All the reformulated samples were judged acceptable by the panellists. At the end of storage, the control sample contained more than four times as much residual nitrite as the reformulated samples. Growth of presumptive Clostridium perfringens was not observed in any of the samples. Samples without added nitrite had longer shelf-lives than control sausage. Samples containing 0.1% vitamin C registered the lowest microbiological levels. This strategy could be a good alternative to reduce and/or eliminate added nitrite in hot dog sausages.

Effects of emulsion gels containing bioactive compounds on sensorial, technological, and structural properties of frankfurters.

Emulsion gels prepared with olive oil, chia, and cold gelling agents (transglutaminase, alginate, or gelatin) were used as fat replacers in reduced-fat frankfurter formulation. Nutritional advantages, sensory analysis, technological properties, and microbiological populations of frankfurters were evaluated along with their lipid structural characteristics over chilled storage. Frankfurters with emulsion gels showed significant improvements in fat content (lower saturated fatty acid, higher mono- and polyunsaturated fatty acid contents) and had good fat and water-binding properties. The presence of an emulsion gel reduced lightness and redness, but increased yellowness. Textural behavior of samples was significantly affected by the presence of emulsion gels and by storage. Sensory properties were not affected by the incorporation of emulsion gels, and all frankfurters were judged acceptable. Attenuated total reflectance-Fourier transform infrared spectroscopy results showed that samples with emulsion gels involve more lipid-protein interactions. Frankfurters with emulsion gels showed good stability to oxidation during storage and contained lower levels of microorganism than reduced-fat control at 85 days.

Nitrite-free Asian hot dog sausages reformulated with nitrite replacers.

This research deals with the application of a global strategy designed to produce a nitrite-free Asian hot dog. Different ingredients such as annatto, cochineal, orange dietary fibre, vitamins E and C, lactate and celery were combined in order to study the appearance (colour), lipid oxidation stability and microbial stability of the nitrite-free formulations. The control sample contained much more (P < 0.05) residual nitrite (88.7 mg/kg) than the samples without added nitrite (23-24 mg/kg). Generally, no formulation-dependent variations were observed in fat and water binding properties. Control sample had the highest L* and a* values, while the product with annatto (RA) had the lowest a* values. Lipid oxidation levels were similar irrespective of formulation. The hot dog reformulated with cochineal (RC) scored higher for overall acceptability than RA, mainly due to its colour.

Oil-in-water emulsion gels stabilized with chia (Salvia hispanica L.) and cold gelling agents: Technological and infrared spectroscopic characterization.

This paper reports on the development of olive oil-in-water emulsion gels containing chia (Salvia hispanica L.) (flour or seed) and cold gelling agents (transglutaminase, alginate or gelatin). The technological and structural characteristics of these emulsion gels were evaluated. Both structural and technological changes in emulsion gels resulting from chilled storage were also determined. The color and texture of emulsion gels depend on both the cold gelling agents used and chilled storage. Lipid oxidation increased (p < 0.05) during storage in emulsion gels containing transglutaminase or alginate. Analyses of the half-bandwidth of the 2923 cm(-1) band and the area of the 3220 cm(-1) band suggest that the order/disorder of the oil lipid chain related to lipid interactions and droplet size in the emulsion gels could be decisive in determining their textural properties. The half-bandwidth of 2923 cm(-1) band and area of 3220 cm(-1) band did not show significant differences during chilled storage.

Raman spectroscopic study of structural changes upon chilling storage of frankfurters containing olive oil bulking agents as fat replacers.

Technological properties and structural characteristics of proteins and lipids, using Raman spectroscopy, of frankfurters formulated with olive oil bulking agents as animal fat replacers were examined during chilling storage. Frankfurters reformulated with oil bulking agents showed lower (P<0.05) processing loss and higher (P<0.05) hardness and chewiness. Purge loss during chilling storage was relatively low, demonstrating a good water retention in the products. ß-Sheet structures were enhanced by the use of olive oil bulking agents, and this effect was more pronounced in samples containing inulin. Reformulated frankfurters contained the least turns (P<0.05). A significant decrease of ß-sheets and an increase of turns were observed after 85 days of chilled storage. The lowest (P<0.05) values of IνsCH2/IνasCH2 were recorded in frankfurters reformulated with oil bulking agents, which suggests more lipid acyl chain disorder. Structural characteristics were correlated to processing losses, hardness, and chewiness.

Oil bulking agents based on polysaccharide gels in meat batters: a Raman spectroscopic study.

A Raman spectroscopic study was performed to determine protein and lipid structural properties in meat batter containing oil bulking agents as pork backfat replacers. Meat batters were prepared with pork backfat (MB-PF) or with a combination of olive oil, sodium alginate, CaSO4, sodium pyrophosphate and dextrin (MB-A/D) or inulin (MB-A/I) as a fat replacer. Proximate composition, pH, cooking loss (CL), colour and texture were evaluated. MB-A/D and MB-A/I both showed lower (P<0.05) CL and a(*) values, higher (P<0.05) L(*) and b(*) values, and higher (P<0.05) hardness and chewiness. MB-A/I showed the highest hardness and chewiness. Enhancement of the ß-sheet structure was observed in MB-A/D and MB-A/I, more so in MB-A/I. There was increased disorder in the oil acyl chains, which involve lipid-protein interactions, in both MB-A/D and MB-A/I. Structural characteristics in proteins and lipids may be associated with specific water and fat binding properties and textural characteristics of meat batters.

Effect of preformed konjac gels, with and without olive oil, on the technological attributes and storage stability of merguez sausage.

In order to improve the fat content of fresh sausages (merguez), the effects of both reducing beef fat level (by konjac gel-KG) and incorporing olive oil (in a konjac matrix-OKM) on nutritional, quality characteristic and refrigerated storage stability were studied. Fat reductions in merguez sausages of between 53 and 76% were achieved when beef fat was replaced with KG; the proportion reached 34-49% using OKM as a beef fat replacer, where 23 to 36% of total fat in the merguez was from olive oil. The merguez contained substantial amounts of some minerals (Mg and Fe). Sensory analysis revealed no significant differences between the control and the reformulated products, which had relatively low levels of lipid oxidation. Shelf life and biogenic amines of merguez sausage were not affected by formulation during refrigerated storage. Therefore, the use of konjac materials as fat replacers could reduce total caloric energy by replacing/reducing beef fat and improving sausage formulation to achieve healthier merguez products.

Enriched n-3 PUFA/konjac gel low-fat pork liver pâté: lipid oxidation, microbiological properties and biogenic amine formation during chilling storage.

Low-fat pork liver pâtés enriched with n-3 PUFA/konjac gel were formulated by replacing (totally or partially) pork backfat by a combination of healthier oils (olive, linseed and fish oils) and konjac gel. Lipid oxidation, microbiological changes and biogenic amine (BA) formation were studied in healthier-lipid pâtés during chill storage (85 days, 2 °C). Increasing unsaturated fatty acid levels favoured lipid oxidation, although the levels reached were low throughout the storage period, ranging from 0.113 to 0.343 mg malonaldehyde/kg sample. Neither the formulation nor the time in storage affected the microbial load. Biogenic amine contents of products (the sum of initial concentrations and amines formed during storage) varied according to the type of BA but were far below levels that could constitute a consumer health hazard.

Konjac gel as pork backfat replacer in dry fermented sausages: processing and quality characteristics.

The effect of replacing animal fat (0%, 50% and 80% of pork backfat) by an equal proportion of konjac gel, on processing and quality characteristics of reduced and low-fat dry fermented sausage was studied. Weight loss, pH, and water activity of the sausage were affected (P<0.05) by fat reduction and processing time. Low lipid oxidation levels were observed during processing time irrespective of the dry sausage formulation. The fat content for normal-fat (NF), reduced-fat (RF) and low-fat (LF) sausages was 29.96%, 19.69% and 13.79%, respectively. This means an energy reduction of about 14.8% for RF and 24.5% for LF. As the fat content decreases there is an increase (P<0.05) in hardness and chewiness and a decrease (P<0.05) in cohesiveness. No differences were appreciated (P>0.05) in the presence of microorganisms as a result of the reformulation. The sensory panel considered that NF and RF products had acceptable sensory characteristics.

Low-fat pork liver pâtés enriched with n-3 PUFA/konjac gel: dynamic rheological properties and technological behaviour during chill storage.

Low-fat pork liver pâtés enriched with n-3 PUFA/konjac gel were formulated by replacing (total or partially) pork backfat by a combination of healthier oils (olive, linseed and fish oils) and konjac gel. Dynamic rheological properties and technological behaviour of pâtés during chill storage (2 °C, 85 days) were analysed. Cooking yields were affected (P<0.05) by formulation, with percentages ranging between 88 and 98%. According to the frequency sweep test, pâtés presented a gel/emulsion-like pattern with a loosely-structured network and the consistency of a viscoelastic gel. Thermal processing caused the formation of a protein gel network with a considerable element of emulsion-like characteristics. Pâtés became lighter and less red (P<0.05) during chill storage. Purge losses of around 1% were observed at the end of the storage period, irrespective of formulation. Textural parameters of pâtés were affected by formulation and storage time. The results suggest that the replacement of pork back fat by oil-in-water emulsion and the incorporation of konjac gel could provide a mixture of ingredients that effectively mimics the normal animal fat content in pâtés.

Infrared study of structural characteristics of Frankfurters formulated with olive oil-in-water emulsions stabilized with casein as pork backfat replacer.

This article reports an infrared spectroscopic (FT-IR) study on lipids and protein structural characteristics in frankfurters as affected by an emulsified olive oil stabilizing system used as a pork backfat replacer. The oil-in-water emulsions were stabilized with sodium caseinate, without (F/SC) and with microbial transglutaminase (F/SC+MTG). Proximate composition and textural characteristics were also evaluated. Frankfurters F/SC+MTG showed the highest (P < 0.05) hardness and lowest (P < 0.05) adhesiveness. These products also showed the lowest (P < 0.05) half-bandwidth of the 2922 cm(-1) band, which could be related to the fact that the lipid chain was more orderly than that in the frankfurters formulated with animal fat and F/SC. The spectral results revealed modifications in the amide I band profile when the olive oil-in-water emulsion replaced animal fat. This fact is indicative of a greater content of aggregated intermolecular ß-sheets. Structural characteristics in both proteins and lipids could be associated with the specific textural properties of frankfurters.

Production of biogenic amines by lactic acid bacteria and enterobacteria isolated from fresh pork sausages packaged in different atmospheres and kept under refrigeration.

The occurrence of in vitro amino acid activity in bacterial strains associated with fresh pork sausages packaged in different atmospheres and kept in refrigeration was studied. The presence of biogenic amines in decarboxylase broth was confirmed by ion-exchange chromatography and by the presence of the corresponding decarboxylase genes by PCR. From the 93 lactic acid bacteria and 100 enterobacteria strains analysed, the decarboxylase medium underestimates the number of biogenic amine-producer strains. 28% of the lactic acid bacteria produced tyramine and presented the tdc gene. All the tyramine-producer strains were molecularly identified as Carnobacterium divergens. Differences on the relative abundance of C. divergens were observed among the different packaging atmospheres assayed. After 28 days of storage, the presence of argon seems to inhibit C. divergens growth, while packing under vacuum seems to favour it. Among enterobacteria, putrescine was the amine more frequently produced (87%), followed by cadaverine (85%); agmatine and tyramine were only produced by 13 and 1%, respectively, of the strains analysed. Packing under vacuum or in an atmosphere containing nitrogen seems to inhibit the growth of enterobacteria which produce simultaneously putrescine, cadaverine, and agmatine. Contrarily, over-wrapping or packing in an atmosphere containing argon seems to favour the growth of agmatine producer-enterobacteria. The production of putrescine and cadaverine was associated with the presence of the corresponding amino acid decarboxylase genes. The biogenic amine-producer strains were included in a wide range of enterobacterial species, including Kluyvera intermedia, Enterobacter aerogenes, Yersinia kristensenii, Serratia grimesii, Serratia ficaria, Yersinia rodhei, Providencia vermicola and Obesumbacterium proteus.

Quality characteristics of low-salt restructured poultry with microbial transglutaminase and seaweed.

Characteristics of restructured poultry steaks as affected by addition of Sea Spaghetti seaweed (3% dry matter) combined with NaCl reduction and a microbial transgutaminase/caseinate (MTGase/caseinate) system as a cold binding agent were studied during chill storage. The incorporation of Sea Spaghetti caused a slight (P<0.05) increase in purge loss but reduced cooking loss in the products. Addition of MTGase/caseinate did not affect water binding properties. The added seaweed and the MTGase/caseinate system both increased (P<0.05), the Kramer shear force (KSF) of raw products, making them easier to handle. No such effect was observed in cooked products. Products with Sea Spaghetti had higher levels (P<0.05) of total viable counts and lactic acid bacteria, and also higher levels of tyramine and spermidine. All products were judged acceptable by a sensory panel. During chill storage no important changes were found in the target properties due to composition.

Technological and sensory characteristics of reduced/low-fat, low-salt frankfurters as affected by the addition of konjac and seaweed.

This paper reports the effect of an edible seaweed, Sea Spaghetti (Himanthalia elongata), on the physicochemical (emulsion stability, cooking loss, colour, texture, residual nitrite and microstructure) and sensory characteristics of reduced- and low-fat, low-salt (NaCl) frankfurters prepared with konjac gel as a fat substitute. The effects on emulsion stability of substituting konjac gel for pork backfat were conditioned by the proportion of the substitution. Incorporation of a combination of Sea Spaghetti/konjac gel (accompanied by reduction in salt) increased (P<0.05) cooking loss and reduced (P<0.05) emulsion stability in the gel/emulsion systems. Incorporation of Sea Spaghetti/konjac gel produced a decrease (P<0.05) of lightness (L*) and redness (a*) values and an increase (P<0.05) of yellowness (b*) as compared to the other samples. The effect of adding seaweed on the texture parameters of low-salt frankfurters varied depending on the proportion of konjac gel used in the formulation. Morphological differences in frankfurter microstructure were observed as fat content was reduced and konjac gel increased. Incorporation of a combination of Sea Spaghetti/konjac gel caused the formation of a more heterogeneous structure, in which the seaweed was integrated in the meat protein matrix.