Biogenic amines in restructured beef steaks as affected by added walnuts and cold storage

Konjac-based oil bulking system for development of improved-lipid pork patties: technological, microbiological and sensory assessment

Improved-lipid pork patties were manufactured following two different reformulation strategies: fat reduction by replacement of pork backfat with konjac gel (KG), and fat reduction/lipid improvement by replacement of pork backfat with an improved oil combination (olive, linseed and fish oils) bulking system based on konjac gel (O-KG). Technological, microbiological and sensory properties were analyzed as affected by the type of formulation and by chilled storage (9days, 2°C). Fat was reduced by between 30 and 86%. In the cases where O-KG was incorporated, 12 and 41% of total fat in patties came from the oil combination. There was no observable effect on color parameters in samples with O-K. Higher KG levels produced harder cooked patties. Animal fat replacement in patties promoted an increase in lipid oxidation, which was more pronounced in samples with an oil combination. In general, during chilled storage no major changes were observed in the studied properties as a result of the different treatments.

Quality characteristics of pork burger added with albedo-fiber powder obtained from yellow passion fruit (Passiflora edulis var. flavicarpa) co-products

The aim of this work determined the technological, nutritional and sensory characteristics of pork burgers, added with different concentrations (2.5 and 5%) of passion fruit albedo (PFA) co-product, obtained from passion fruit juice processing. The addition of PFA on pork burgers improves their nutritional value (higher fiber content). In raw and cooked burger, all textural parameters, except springiness and cohesiveness, were affected by the incorporation of PFA. PFA addition was found to be effective improving the cooking yield, moisture retention and fat retention. The raw and cooked pork burgers added with PFA had lower TBA values and lower counts of aerobic mesophilic bacteria and enterobacteria than the control samples. No Escherichia coli and molds were found in the samples. The overall acceptability scores showed that the most appreciated sample was the one containing 2.5% PFA. According to the results obtained, 2.5 and 5% of PFA addition can be recommended in pork burger production as a new dietary fiber source.

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.

Biogenic amines in low- and reduced-fat dry fermented sausages formulated with konjac gel

Biogenic amines in low- and reduced-fat dry fermented sausages made with konjac gel (KG) as pork backfat replacer were studied. An increase (P < 0.05) was observed in the microbial count during the fermentation process, reaching levels of over 8 Log cfu/g of total viable microorganisms and lactic acid bacteria. However, no significant differences were observed in the microbiota evolution as a function of the reformulation process (fat and konjac gel content). High levels of physiological amines (spermidine, spermine, and agmatine) were observed in the raw material. From day 2 of the fermentation process an increase (P < 0.05) was observed in tyramine and putrescine, which were the predominant amines at the end of the storage period. The increase in these amines was proportional to the presence of KG and fat reduction. This can also be seen for spermine, with agmatine showing the inverse. The biogenic amine levels in these products reformulated with KG are not considered to pose a health risk to consumers.

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.

Influence of dietary catechols on the growth of enteropathogenic bacteria

The dietary constituents that may act, in the broadest sense, as co-factors to enable bacterial enteropathogens to replicate in gastrointestinal environments are still largely unknown. Recent work has demonstrated that certain non-nutritional components of food, such as the catecholamines, can contribute to the ability of Gram-negative pathogens to replicate in iron-restrictive media that may be reflective of gastrointestinal environments. The present report examines whether other, non-catecholamine, dietary catechols, which occur widely in plant foods, can also influence enteropathogen growth in an iron-restrictive environment such as might be found in the gastrointestinal tract. In the present study, we have examined the ability of a range of catechol-rich foodstuffs, ranging from beverages (tea and coffee) to fruit and vegetable extracts, as well as purified preparations of commonly consumed dietary catechols (catechins, chlorogenic acid, caffeic acid and tannic acid), to modulate the growth of the Gram-negative enteric pathogens Escherichia coli O157:H7 and Salmonella enterica SV Enteriditis. Time-dependent growth in response to dietary catechols (0.05-5.0% v/v of beverage or fruit/vegetable extracts; 10-200 microM of purified catechols) was examined in an iron-replete, rich medium as well as in an iron-limited, basal medium designed to reflect the iron-restricted environment that is more characteristic of human and animal tissues. Results obtained in iron-replete, rich medium demonstrated dose-dependent bacteriostatic effects for certain catechols, consistent with previous studies. However, in iron-restricted medium, all of the dietary catechols produced marked growth stimulation of up to 4 logs greater than non-supplemented controls. Mechanistic studies measuring the uptake of radiolabelled (55)Fe from (55)Fe-labelled lactoferrin and transferrin in bacteria grown in the presence or absence of dietary catechols demonstrated that the ability of catechols to stimulate bacterial growth was dependent on the provision of iron from iron-sequestering glycoproteins. Urea gel analysis of transferrin incubated in the presence of the dietary catechols confirmed that these compounds were directly chelating and removing transferrin-complexed iron. Analysis using E. coli O157:H7 entA and tonB mutants further showed that a functional siderophore synthesis and uptake system was required for the growth-stimulatory response. In contrast to previous studies, which have reported the anti-microbial activity of dietary catechols, the present study demonstrates that these non-nutritional components of foods can, under iron-restrictive conditions, provide iron and enable the growth of enteric bacterial pathogens.

Biologically active polyamines in beef, pork and meat products: A review

Dietary polyamines (PAs) putrescine (PUT), spermidine (SPD) and spermine (SPM) participate in an array of roles in human metabolism. Nevertheless, under some physiological conditions they can be undesirable. Meat and meat products are among important sources of PAs in human nutrition, mainly of SPM. The usual contents of PUT, SPD and SPM in fresh beef and pork are <2, <5 and 20-40mgkg(-1), respectively. Current information on changes of PAs during meat storage corresponds with PUT formation by bacterial activity mainly of pseudomonads and Enterobacteriaceae. However, data on SPD and SPM changes during meat chill-storage have been inconsistent. Culinary processing of meat probably does not change SPD and SPM levels. PUT can be formed in different meat products in relation to the microbial population of the raw materials used and the hygienic level of manufacturing process. SPD and SPM contents seem to remain stable during processing of non-fermented meat products or decrease during dry-cured ham ripening. PUT contents increase commonly to 60-140mgkg(-1) in dry spontaneously fermented sausages, however, contents up to several hundreds mgkg(-1) are not extraordinary. Starter cultures are usually able to decrease PUT formation considerably. SPD and SPM contents in dry fermented sausages are comparable with levels typical for fresh meat. Data on SPD and SPM changes during ripening and storage are inconsistent. A decrease of the both polyamines during a storage period has been usually reported.