Changes in benzo(a)pyrene content in fermented salami

Summary The benzo(a)pyrene (BaP) content of fermented salami was monitored during the technological processes of cold smoking, ripening and storage. The changes in BaP content were not so great as in products smoked with hot smoke. However, the decrease in BaP content caused by destructive action of physico-chemical environmental factors was compensated by succesive dehydration of the fermented product. After recalculating the BaP content on a dry weight basis a concentration decrease was evident. Significant changes were registered during smoking and ripening while storage under different conditions caused no further effect on these changes.

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Gehaltsänderungen an Benzo(a)pyren in fermentierten Salamiwurst

Zusammenfassung Die Arbeit befaßt sich mit Untersuchungen der Änderungen im Benzo(a)pyren-Gehalt in fermentierter Salamiwurst. Diese Änderungen wurden nicht nur während des Räucherungsprozesses mit kaltem Rauch untersucht, sondern auch im Verlauf des Reifeprozesses und der Lagerung des Produktes unter verschiedenen Bedingungen. Aus diesen Ergebnissen kann man feststellen, daß Gehaltsänderungen an Benzo(a)pyren nicht so markant sind wie bei mit warmem Rauch geräucherten Produkten. Andererseits wird die Abnahme an Benzo(a)pyren durch die destruktive Wirkung der physikalisch-chemischen Faktoren der Umwelt durch die successive Dehydratation des fermentierten Produktes kompensiert. Nach Umrechnung des Gehaltes von Benzo(a)pyren auf Trockensubstanz ist aber die Abnahme evident. Markante Änderungen ergaben sich im Laufe der Räucherung und Reifung, während die Lagerung unter verschiedenen Bedingungen ohne Wirkung war.

     

Use of Fourier transform infrared spectroscopy to evaluate the proteolytic activity of Yarrowia lipolytica and its contribution to cheese ripening

The interaction between tyrosine-decarboxylase and proteolytic activities of a Lactobacillus curvatus and Staphylococcus xylosus, respectively, on biogenic amine production during the ripening and the storage of dry fermented sausages was investigated. Water content, pH, proteolysis parameters, microbial counts, and biogenic amine contents were monitored in spontaneously and starter fermented sausages. The use of proteolytic staphylococci as starter resulted in a higher content of non-protein nitrogen and total free amino acids. Tyramine was the main amine produced in all batches. However, tyrosine-decarboxylase activity of the L. curvatus starter strain was weak and yielded lower amounts of tyramine than those produced by the wild mioroflora in the control batch. Association between tyramine production and proteolysis could only be established in a defectively dried batch. Putrescine and cadaverine accumulation was efficiently reduced in the starter-mediated fermentation, in agreement with the lower development of enterobacteria. Phenylethylamine and tryptamine were only detected in the spontaneously fermented sausages, while histamine, spermine and spermidine did not vary during the ripening. Biogenic amine levels and related parameters showed significant changes during the storage of dry sausages depending on the temperature and the batch. As a general rule, changes in the pH, proteolysis, microbial counts, and biogenic amine contents were stronger at 19 degrees C than at 4 degrees C. The results suggest that refrigeration would be advisable for preventing further accumulation of biogenic amines during the storage of dry fermented sausages.     

Effect of pasteurization and fermentation on residues of sulphonamides in sausages

The different effects of pasteurization and fermentation on sulphamethazine (SMZ) and sulphachlorpyridazine (SCP) were investigated in two common German meat products, luncheon meat and raw fermented sausages. There was no decrease in sulphonamide concentration (5 μg g^-1) in luncheon meat during the different stages of processing and storage (4°C up to 27 days). Less than 40% of the initial concentration remained in fermented sausages after ripening for 10 days in a climatized room. The sulphonamide content was reduced only if fermentation was involved in contrast with meat contaminated with other chemotherapeutic residues.     

Influence of cooking on benzo(a)pyrene content in smoked sausages

The changes in benzo(a)pyrene (BaP) content of smoked sausages were monitored during 1 h cooking. During this time, the BaP content decreased from 4·80 to 1·87 μg/kg. The maximum drop in BaP content was reached in the first 20 min of cooking. Two factors affected the course of BaP changes, viz. water-holding capacity and the fat content. After excluding these factors, there was a high correlation coefficient of 0·996 between time of cooking and BaP content, which confirmed an inverse relationship between the decrease in BaP content and time of cooking.

The BaP decrease was directly proportional to the decrease of fat content during cooking, when the relatively high BaP content of 7·71 μg/kg was found in the cooked-out fat.     

Sensory acceptability of slow fermented sausages based on fat content and ripening time

Low fat dry fermented sausages were manufactured using controlled ripening conditions and a slow fermented process. The effect of fat content and ripening time on the chemical, colour, texture parameters and sensory acceptability was studied. The fat reduction in slow fermented sausages produced an increase in the pH decline during the first stage of the process that was favoured by the higher water content of the low fat sausages. Fat reduction did not affect the external appearance and there was an absence of defects but lower fat content resulted in lower sausage lightness. The sausage texture in low fat sausages caused an increase in chewiness and at longer ripening times, an increase in hardness. The sensory acceptability of the fermented sausages analyzed by internal preference mapping depended on the different preference patterns of consumers. A group of consumers preferred sausages with high and medium fat content and high ripening time. The second group of consumers preferred sausages with low ripening time regardless of fat content except for the appearance, for which these consumers preferred sausages of high ripening time. Finally, the limit to produce high acceptability low fat fermented sausages was 16% fat content in the raw mixture that is half the usual content of dry fermented sausages.     

发酵酸肉煮制过程品质动力学研究

利用动力学分析发酵酸肉在70~80℃水浴加热过程中成熟因子(色泽、剪切力)及过热因子(水分活度、水分含量)动力学变化过程。结果表明:随着加热温度的升高,发酵酸肉成熟因子(色泽、剪切力)及过热因子(水分活度、水分含量)变化均符合一级动力学方程,其中亮度值的Z值为63.751℃,Ea值为4.016kJ/mol;红度值变化Z值为35.500℃,Ea值为4.029kJ/mol,黄度值变化Z值为32.459℃,Ea值为4.031kJ/mol。剪切力Z值为102.070℃,Ea值为4.047kJ/mol。水分活度的Z值为55.118℃,Ea值为3.643kJ/mol。水分含量Z值为-2.366℃,Ea值为4.034kJ/mol。发酵酸肉煮制过程成熟因子色泽红度值、黄度值的Z值小于水分活度Z值,成熟品质因子亮度值、剪切力的Z值大于过热品质因子水分活度、水分含量的Z值,亮度值、剪切力值的变化与优化烹饪条件结论相反,说明发酵酸肉加热过程中其成熟及过热因子均存在优化空间,可以通过优化加热条件进一步改善发酵酸肉品质变化。     

The effect of three different ripening/storage conditions on the distribution of selected parameters in individual parts of Dutch‐type cheese

The aim of the study was (i) to detect changes of dry matter, NaCl and twenty‐two free amino acids contents, pH and levels of selected microorganisms in four layers of cheese (from edge to core) during ripening and storage period and (ii) to describe the changes of the above‐mentioned parameters caused by early relocation of cheese from optimum ripening conditions to refrigeration temperatures. The number of mesophilic aerobic and facultative anaerobic bacteria and lactic acid bacteria differed significantly (P < 0.05) during the experiment dependent on the analysed layer and ripening/storage conditions. The free amino acid content differed significantly in individual analysed layers of cheese and also according to individual ripening/storage conditions. The highest content of free amino acids was found in samples stored at optimal ripening temperatures. Cheese hardness was also analysed and the lowest one was detected in samples ripened under optimal temperatures for the whole period. Early release of cheeses into storage rooms with lower temperature significantly affected properties of these products.     

Changes in biogenic amine and polyamine contents in slightly fermented sausages manufactured with and without sugar

The effect of sugar omission on biogenic amine contents of slightly fermented sausages during ripening and storage was evaluated. Two batches of spontaneously fermented sausages were produced with and without sugars in two different trials at pilot-plant scale. Ripened sausages were stored at 4 and 19°C for a further 20 days. Tyramine and cadaverine were the main amines formed during ripening, their contents being significantly higher in batches without sugar. High counts of LAB and Enterobacteriaceae could be associated with the production of tyramine and cadaverine, respectively. The occurrence of putrescine depended on the trial and batch. Sausages without sugar contained more putrescine than those with sugar in trial 1, but this was not repeated in trial 2, in which a high production of agmatine occurred. Tryptamine and phenylethylamine were only detected in the later stages of ripening, their contents also being higher in sausages without sugar. Biogenic amine contents generally rose during storage at 19°C, the increase being especially important for cadaverine and tyramine in sausages without sugar. Levels of spermidine and spermine remained constant during ripening and decreased slightly during storage. Sugar omission is not recommended because it might increase biogenic amine accumulation during the manufacture and storage of slightly fermented sausages.     

Ripening temperature affects the content and distribution of isoflavones in sufu,a fermented soybean curd

Sufu, a fermented soybean curd, was prepared by ripening the salted tofu cubes in the Aspergillus oryzae‐fermented rice–soybean koji mash at 25, 35 or 45 °C for a period of 16 days. It showed that the 16‐day ripened sufu contains less total isoflavone content (629.29–739.68 μg g^?1 dried matter) than the salted tofu before ripening (942.59 μg g^?1 dried matter). Regardless of ripening temperature, ripening causes a major reduction in the content of β‐glucoside and malonylglucoside isoflavones along with a significant increase of aglycone isoflavone content. These changes were enhanced as the ripening period extended. Among the various treatments examined, sufu ripened at 45 °C showed the greatest increase in aglycone content coupled with the greatest decrease in malonylglucosides. The distribution of malonylglucosides decreased from an initial 40.32% in the tofu cube to 9.78% after 16 days of ripening at 45 °C. Meanwhile, the distribution of aglycone increased from 13.17% to 39.88%.     

Use of bacterial extracts to enhance amino acid breakdown in dry fermented sausages

The effect of the intracellular cell-free extracts (ICFEs) of two bacterial strains (Lactobacillus sakei GO and Bacillus pumilus) on the amino acid catabolism and the sensory properties of dry fermented sausages, was investigated. Extracts were added to sausages alone or in combination with a protease, papain. Amino acid breakdown was monitored by the changes in free amino acids, ammonia and amine content during the ripening process. A 15% decrease in the content of free amino acids was observed in sausages added with the ICFE from L. sakei GO. Furthermore, the extract of L. sakei GO significantly reduced (54-68%) the content of the amino acids considered as precursors of the typical ripened flavour, i.e., valine, leucine and isoleucine. Chemical changes were not reflected in a significant improvement of the sensory quality of sausages added with the ICFEs. The potential use of the bacterial ICFEs studied in the present work for the manufacture of dry fermented sausages, and its comparison with the use of fungal extracts, are discussed.     

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.     

原料肉贮藏时间对牛肉发酵香肠中微生物菌相变化和蛋白质降解的影响

采用传统微生物计数、高通量测序、凯氏定氮、高效液相色谱等方法,探究牛肉宰后0～4 ℃下不同贮藏时间（0、12、24、36 h）对发酵香肠加工过程中微生物菌相变化、蛋白质降解及其相关性的影响。结果显示,随着牛肉贮藏时间的延长,香肠中菌落总数、大肠菌群数、菌群多样性和丰富度以及蛋白质降解指标均呈上升趋势,总游离氨基酸含量呈下降趋势;香肠成熟阶段中总挥发性盐基氮含量与总生物胺含量之间呈极显著正相关（P＜0.01）。其中,贮藏36 h牛肉加工的香肠与未经贮藏牛肉加工的香肠对比,菌落总数平均值由2.40×107 CFU/g增加到4.03×107 CFU/g（P＜0.05）,反映菌群多样性的Shannon指数平均值由1.39增长至2.89,优势菌群由整个加工阶段均为葡萄球菌变成前期为魏斯氏菌,后期为葡萄球菌;总游离氨基酸含量平均值由7.09 mg/g减少至6.44 mg/g,总生物胺含量平均值由92.14 mg/kg增长为117.42 mg/kg（P＜0.05）。结论：控制原料牛肉贮藏时间可以有效减少香肠中微生物的总量,降低菌群多样性,抑制蛋白质的降解,减缓生物胺的积累,从而保障发酵香肠的安全性。     

Benzo(a)pyrene penetration on a smoked meat product during smoking time

The Codex Alimentarius gives recommendations to prevent carcinogenic polycyclic aromatic hydrocarbons (PAH) (represented by benzo(a)pyrene (BaP)) contamination during processing of meat products, including the control of smoking time. The influence of direct smoking time (0, 1, 3, 5 and 7 days) on the relationship between the BaP and moisture content of a typical Spanish smoked meat product called chorizo and the mechanism of BaP penetration and water release from four different depths in the product was studied. Chorizo was studied from the Principality of Asturias, a location never before tested. An analytical method was developed for this purpose consisting of PAH extraction assisted by sonication followed by solid-phase extraction (SPE) sample clean-up and analytical determination using GC-MS. Results show that an increase in smoking time produced contradictory and independent effects on the moisture and BaP content (µg kg^–1) of chorizos. The moisture content decreased from 49.9% to 31.3%. On the other hand, the BaP content increased from less than 0.24 µg kg^–1 to 0.75 µg kg^–1, finally stabilising after 5 days of smoking. After this time, the natural pores of the casing could be blocked by the large size tar particles from smoke, preventing the continued penetration of PAHs. The BaP content decreased and the moisture content increased progressively from the casing to the centre of the meat product. BaP mainly accumulated in the smoked casing, being four times in excess of the legal limit. This paper analyses the mechanism for preventing PAHs contamination during the process of smoking meat products.     

Effect of starter culture and storage temperature on the content of biogenic amines in dry fermented sausage poličan

Water activity, pH, microbial counts (total counts/TCM/, coliforms, Enterobacter, Proteus, Pseudomonas, Escherichia and Lactobacillus spp., respectively), and seven biogenic amines (BA) were determined in dry fermented sausage 'poli?an' produced using starter culture A (Lactobacillus sakei, Staphylococcus carnosus, S. xylosus) or B (L. sakei, S. carnosus, Pediococcus pentosaceus), ripened 42 days, and subsequently stored at 8 or 22°C 60 days. Counts of lactobacilli were higher and TCM lower in the A-sausage when ripening was finished. Tyramine (quantitatively most important BA) content was not different (P>0.05) in A- (90 mg/kg of dry matter, DM) or B-sausage (91 mg/kg DM) at the end of ripening. The effect of the storage temperature on BA content was not significant (P>0.05) in the case of either tyramine or any other tested BA. The increase of total BA content during ripening was not different (P>0.05) between A- and B-sausages (final value 190 and 222 mg/kg DM, respectively). However, sum of BA was significantly higher (P<0.05) in B-sausage as compared with A-sausage at the end of either refrigerated storage (304 and 236 mg/kg DM) or room temperature storage (468 and 206 mg/kg DM, respectively). It is concluded that legislative limits should be established for tyramine and total BA content in dry fermented meat products.     

植物乳杆菌发酵枣汁在冷藏期间的营养品质变化研究

以陕北木枣、新疆和田枣为原料,经植物乳杆菌（Lactobacillus plantarum）发酵制备发酵枣汁,分析两种发酵枣汁在冷藏过程（4 ℃、28 d）中的理化特性、酚类化合物、抗氧化活性以及风味特征变化。结果表明,在冷藏过程中发酵枣汁的活菌数逐渐减少,但28 d后发酵枣汁中活菌数仍高于6.0 lg（CFU/mL）。冷藏过程中发酵枣汁总糖和还原糖含量有所降低,可滴定酸含量有所升高。冷藏28 d后的发酵枣汁总酚含量高于冷藏前的发酵枣汁,冷藏过程较好地保持了发酵枣汁的1,1-二苯基-2-三硝基苯肼（DPPH）自由基清除活性和铁离子还原能力。经过冷藏后的枣汁中风味物质含量相较于冷藏前的发酵枣汁有所降低,但始终高于未发酵枣汁,植物乳杆菌发酵赋予枣汁丰富的花香和果香。     

Fermentation of Cucumbers Brined with Calcium Chloride Instead of Sodium Chloride

ABSTRACT: Waste water containing high levels of NaCl from cucumber fermentation tank yards is a continuing problem for the pickled vegetable industry. A major reduction in waste salt could be achieved if NaCl were eliminated from the cucumber fermentation process. The objectives of this project were to ferment cucumbers in brine containing CaCl₂ as the only salt, to determine the course of fermentation metabolism in the absence of NaCl, and to compare firmness retention of cucumbers fermented in CaCl₂ brine during subsequent storage compared to cucumbers fermented in brines containing both NaCl and CaCl₂ at concentrations typically used in commercial fermentations. The major metabolite changes during fermentation without NaCl were conversion of sugars in the fresh cucumbers primarily to lactic acid which caused pH to decrease to less than 3.5. This is the same pattern that occurs when cucumbers are fermented with NaCl as the major brining salt. Lactic acid concentration and pH were stable during storage and there was no detectable production of propionic acid or butyric acid that would indicate growth of spoilage bacteria. Firmness retention in cucumbers fermented with 100 to 300 mM CaCl₂ during storage at a high temperature (45 °C) was not significantly different from that obtained in fermented cucumbers with 1.03 M NaCl and 40 mM CaCl₂. In closed jars, cucumber fermentations with and without NaCl in the fermentation brine were similar both in the chemical changes caused by the fermentative microorganisms and in the retention of firmness in the fermented cucumbers.     

Influence of starter cultures on the generation of antioxidant nitrogen compounds in Iberian dry‐fermented sausages

The purpose of this work was to investigate the influence of a starter culture on the generation of nitrogen compounds with antioxidant activity during the ripening of Iberian dry‐fermented sausages. Starters P200S34 (P. acidilactici M200 and S. vitulus RS34) and P198S34 (P. acidilactici MS198 and S. vitulus RS34) were used to make the Iberian dry‐fermented sausages ‘salchichón’ and chorizo; then, the physicochemical and microbial properties were determined during the ripening process. The oxygen radical absorbance capacity (ORAC) assay was employed to evaluate the antioxidant potential of the nitrogen extracts obtained during ripening of the sausages. This activity was correlated with the most relevant compounds detected by HPLC‐ESI‐MS in the final ripened extracts. Although a relevant part of the antioxidant activity was attributed to the predominant natural nitrogen fraction, the microbial population found in fermented sausages and the fermentation conditions significantly influenced the low molecular weight nitrogen profile and antioxidant activities. Inoculation with the starter culture P200S34 increased free amino acids and amines, such as methionine and tyramine, but other nitrogen compounds also increased the antioxidant activity of the low molecular weight nitrogen extracts. Thus, these starter cultures in Iberian sausages can contribute to delaying oxidative changes during storage.     

干发酵香肠中的生物胺

综述干发酵香肠中生物胺产生的条件,国外干发酵香肠中常见生物胺的种类及含量,与生物胺积累有关的微生物以及影响生物胺产生的理化因素,并提出了控制干发酵香肠中生物胺积累的措施。     

剁椒山笋后熟过程中微生物与挥发性风味物质的相关性分析

采用高通量测序技术和顶空固相微萃取-气相色谱-质谱联用技术测定剁椒山笋后熟过程中微生物多样性和挥发性风味物质的变化,并分析了两者之间的潜在相关性。结果表明：刺盘孢属（Colletotrichum）、青霉菌属（Penicillium）、黄单胞菌属（Xanthomonas）、欧文氏菌属（Erwinia）、劳尔氏菌属（Ralstonia）、假单胞菌属（Pseudomonas）、片球菌属（Pediococcus）和肠杆菌属（Enterobacter）在剁椒山笋后熟贮藏过程中占据主导优势。在发酵过程中共检测到71种挥发性化合物,总含量从406.57μg/kg上升至900.08μg/kg。通过主成分分析得出剁椒山笋样品在后熟初期与末期分离明显。由正交偏最小二乘判别分析变量投影重要性大于1筛选出28种重要代谢物。Pearson相关性分析表明,细菌对风味的影响大于真菌,且优势菌与多数风味物质呈正相关。本研究将为发酵辣椒制品后熟贮藏过程中风味品质的改善提供理论基础。     

The effect of starter cultures on proteolytic changes and amino acid content in fermented sausages

The main objective of this work was to examine the effects of using five types of commercial starter cultures in fermented sausages. During the fermentation stage, changes in proteolytic characteristics were observed in fermented sausages. Proteolytic activity was high in Ls_b + Sc:(Lactobacillus sakei + Staphylococcus carnosus) and Pp + Sx:(Pediococcus pentosaceus + Staphylococcus xylosus) starter-inoculated sausages during processing. Moreover, a slight increase in proteolytic activity was detected during storage in both these sausages. Sarcoplasmic and myofibrillar proteins were also affected by this starter culture addition, during the fermentation, ripening and intense proteolysis were observed in both the fermented sausages. The content of free amino acids was similar at the beginning of the fermentation stage for all the studied batches. However, the high differences in the content of free amino acids at the end of the process could be attributed to the starter culture activity.