Lipolysis in dry cured sausages as affected by processing conditions

Changes of phospholipids and free fatty acids during fermentation and ripening steps of the Spanish dry cured sausage ('salchichón') process have been analyzed by studying the effects of manufacturing conditions; namely starter addition, pre-ripening and drying temperature. Phospholipid concentration of all types of samples considered (with or without starter, preripened or not) showed no important changes during fermentation, but different behaviour was observed during ripening in relation to sample type and drying temperature. At 8 °C concentrations did not change in sausages without starter and suffered a moderate decrease in samples with starter. At 16 °C the decrease was pronounced in samples without starter and much more in those with starter. Pre-ripening had no effect on phospholipid concentration. Free fatty acids increase slightly with pre-ripening, but during fermentation pre-ripened samples showed no more variation, whereas in non-preripened samples an important increase was observed. These results were similar in samples with and without starter. During the ripening step, samples with starter dried at 8 °C showed a higher increase of free fatty acids than those without starter, with no influence of the pre-ripening. At 16 °C all samples showed a higher increase than any sample dried at 8 °C. The maximum was found with non-preripened samples without starter and the minimum with pre-ripened ones, also without starter. Sausages with starter showed an intermediate increase with no effect of pre-ripening.     

Stability of linseed oil and antioxidants containing dry fermented sausages: A study of the lipid fraction during different storage conditions

Different packaging conditions (aerobic, vacuum and modified atmosphere) were evaluated in order to study the stability of the lipid fraction of dry fermented sausages manufactured with a partial substitution of pork backfat by linseed oil and antioxidants. After 5 months of storage, α-linolenic acid was better preserved by vacuum and MAP (7.32 and 7.74g/100g fatty acids, respectively) than in aerobic conditions (6.15g/100g fatty acids), without significant differences to values obtained after 2 months of storage for this acid. At the end of the storage, (n-6)/(n-3) fraction in sausages with linseed oil was in all cases lower than 3, in contrast to values obtained for control products that were all higher than 15. Better PUFA/SFA ratios were also observed in modified sausages (0.6-0.7g/100g fatty acids) than control ones (0.3-0.4g/100g fatty acids). No signs of lipid oxidation measured by TBARs and peroxides were detected for modified sausages regardless the packaging system used (TBARs values lower than 0.25ppm and peroxides lower than 4meq O(2)/kg), pointing at a high effectiveness of the antioxidants. Furthermore, vacuum and MAP prevented 2,4-decadienal formation. Nutritional benefits of linseed oil and antioxidants containing products were maintained after 5 months of storage.     

鲶鱼发酵香肠的研制

为了获得质量、口感较好的鲶鱼发酵香肠,通过发酵剂适应性试验,选择用戊糖片球菌,植物乳杆菌和木糖葡萄球菌按1:1:1比例混合生产鲶鱼发酵香肠,在接种量、温度、相对湿度单因素试验的基础上结合正交实验,通过感官评价,确定鲶鱼发酵香肠的最佳生产工艺。试验结果表明:鲶鱼发酵香肠的最佳生产工艺为:三种菌的接种量为106cfu/g,发酵温度为25℃,发酵相对湿度为90%。     

A comparative study on the effect of some antioxidants on the lipid and pigment oxidation in dry-fermented sausages

A comparative study on the effect of antioxidants on the lipid and pigment oxidation in Bulgarian dry‐fermented sausage type lukanka is described. A commercial mix of antioxidants, called ‘grindox 1021’ (GR), restricted the development of the peroxidation processes in dry‐fermented sausages (type lukanka) to a greater extent than either rosemary (RS), rutine (RT), sodium erythrobate (SE) or l ‐ascorbic acid, when applied at the same concentration. The latter compounds did not effectively stabilize lipids in sausages against oxidation; they only slowed down the lypolysis and did not greatly change the colour of the cross‐sectional surface. However, the sausage lipids were best stabilized when 1 g kg^?1 GR, RS or RT was added. The addition of 1 g kg^?1 RS and GR most efficiently suppressed the hydroperoxides – primary derivatives of lipid peroxidation, while the secondary derivatives in the final product were most reduced when 1 g kg^?1 GR and SE were added.     

Effect of processing conditions on the quality of naturally fermented Turkish sausages (sucuks)

Effects of temperature and different fat levels on the quality of Turkish sausages (sucuks) were studied during the ripening period. Sausage batters prepared at 10%, 20% and 30% fat levels were processed at 20-22 and 24-26 °C. A high ripening temperature and low fat level caused fast dehydration. Fat level affected water activity, colour, total viable and lactic acid bacteria counts of the sausages. Increasing fat content and ripening temperature resulted in high lightness (L*) and yellowness (b*) and low redness (a*) at the end of ripening. The sausages with 10% fat resulted in higher redness values. Growth of total viable and micrococci-staphylococci bacteria was affected by ripening temperature. Sausages ripened at 24-26 °C had a rapid increase in micrococci-staphylococci counts.     

Effect of storage and packaging on fatty acid composition and oxidation in dry fermented sausages made with added olive oil and antioxidants

Dry fermented sausages produced by a partial substitution of pork backfat with pre-emulsified olive oil were manufactured and stored (2 and 5 months) using different packaging conditions (aerobic/vacuum piece/vacuum slices) in order to evaluate the intensity of the oxidation process. Also the effect of the addition of butylhydroxytoluene (BHT) and butylhydroxyanisole (BHA) to one of the modified batches was studied. Addition of olive oil, especially with antioxidants, was more effective than using vacuum storing methods in avoiding lipid oxidation during storage. After 5 months of storage at 4 °C, the combination of the increase in oleic acid and the preservation of PUFA by the antioxidant activity of the olive oil emulsion and antioxidants (when added), lead to better MUFA+PUFA/SFA ratios in olive oil containing sausages (1.90-1.98 g/100 g fatty acids) and particularly in antioxidants containing sausages (2.02-2.16 g/100 g) than in control ones (1.72 g/100 g). Vacuum packaging of the piece was the best method to minimise formation of lipid oxidation volatile compounds.     

Probiotics in fermented sausages

Probiotic foods receive market interest as health-promoting, functional foods. They have been introduced in a wide range of food industries. However, commercial application of probiotic microorganisms in fermented sausages is not common yet. There are both advantages and disadvantages connected to fermented meat matrices. They are adequate for the carriage of probiotic bacteria since they are usually not or only mildly heated and may promote the survival of probiotic bacteria in the gastrointestinal tract. In contrast, bacterial viability may be reduced due to the high content in curing salt and the low water activity and pH. Therefore, results are expected to be strain-dependent. Up till now, several approaches have been followed but most results are too preliminary to be able to evaluate the effect of probiotic fermented meats on human health. Candidate probiotic strains have been obtained through screening for technological requirements among bacteria that are naturally present in the meat or that originate from meat starter cultures. Alternatively, existing probiotic bacteria have been applied in meat products. Finally, the evaluation of the end-products needs to deal with both health effects and technological characteristics, for instance through human intervention studies and taste panels, respectively.     

Lipolysis,lipid peroxidation and texture of Serrano ham processed under different ripening temperature conditions

Lipolysis, lipid peroxidation, texture and rancid taste were investigated in Serrano hams processed under low, medium and high ripening temperature conditions (RTC) for 15 months. Medium RTC hams showed the highest contents of saturated and monounsaturated free fatty acids (FFAs) from month 5 to 15 and of polyunsaturated FFAs from month 7 to 12. The primary peroxidation index decreased during ripening in all hams, with higher levels for low RTC hams from month 5 onwards. Contrarily, the secondary peroxidation index increased during ripening in all hams, with higher levels for medium RTC hams from month 7 onwards. Texture parameters varied significantly among ham muscles. Shear force increased during ripening in all hams, with higher values for medium RTC hams, whereas cutting force was not influenced by RTC or ripening time. Rancid taste scarcely developed during ripening and was not affected by RTC.     

Lipid oxidation in n-3 fatty acid enriched Dutch style fermented sausages

Dutch style fermented sausages were manufactured with a substitution of 10%, 15% and 20% of pork backfat by flaxseed oil and canola oil, pre-emulsified with soy protein isolate. The 15% and 20% substitution were also reached by adding encapsulated flaxseed oil and encapsulated fish oil and by adding flaxseed oil, pre-emulsified with sodium caseinate, respectively. The products were sliced, packaged in an oxygen-enriched atmosphere and stored in the dark for 12 weeks at 7°C. No differences were detected in moisture, protein and fat content between control and modified sausages, with the exception of the formulation with sodium caseinate. The PUFA/SFA ratio increased from 0.30 in the control to 0.42-0.48 in the sausages with canola oil and to 0.49-0.71 in the sausages with flaxseed oil. The n-6/n-3 ratio decreased from 11.20 in the control to 6.94-5.12 in the sausages with canola oil and to 1.93-1.05 in the sausages with flaxseed oil. The addition of canola oil and encapsulated flaxseed oil resulted in a comparable shelf life as the control in terms of lipid oxidation. In the samples with addition of pre-emulsified flaxseed oil, especially with sodium caseinate, lipid oxidation clearly increased during storage. Physical and sensory analysis showed that the sausages with encapsulated fish oil and flaxseed oil resembled the control most.     

不同发酵剂对发酵香肠色泽和质地的影响

本试验采用色差计和质构仪对发酵香肠的色泽和质地进行了测定。添加发酵剂的发酵香肠与对照色泽和质地指标均有显著性差异,不同发酵剂之间质地指标差异不显著而色泽变化差异显著。其中质地指标硬度、胶粘性和咀嚼性与香肠的pH和Aw有显著的相关性。     

Effect of fat content on aroma generation during processing of dry fermented sausages

Dry fermented sausages with different fat contents were produced (10%, 20% and 30%). The effect of fat content and ripening time on sensory characteristics, lipolysis, lipid oxidation and volatile compounds generation was studied. Also, the key aroma components were identified using gas chromatography (GC) and olfactometry. High fat sausages showed the highest lipolysis and lipid oxidation, determined by free fatty acid content and thiobarbituric acid reactive substances (TBARS), respectively. A total of 95 volatile compounds were identified using SPME, GC and mass spectrometry (MS). Fat reduction decreased the generation of lipid derived volatile compounds during processing while those generated from bacterial metabolism increased, although only at the first stages of processing. The consumers preference in aroma and overall quality of high and medium fat sausages was related to the aroma compounds hexanal, 2-nonenal, 2,4-nonadienal, ethyl butanoate and 1-octen-3-ol which contributed green, medicinal, tallowy, fruity and mushroom notes.     

Fatty acid composition, antioxidants and lipid oxidation in chicken breasts from different production regimes

Chicken breast from nine products and from the following production regimes: conventional (chilled and frozen), organic and free range, were analysed for fatty acid composition of total lipids, preventative and chain breaking antioxidant contents and lipid oxidation during 5 days of sub‐ambient storage following purchase. Total lipids were extracted with an optimal amount of a cold chloroform methanol solvent. Lipid compositions varied, but there were differences between conventional and organic products in their contents of total polyunsaturated fatty acids and n‐3 and n‐6 fatty acids and n‐6:n‐3 ratio. Of the antioxidants, α‐tocopherol content was inversely correlated with lipid oxidation. The antioxidant enzyme activities of catalase, glutathione peroxidase and glutathione reductase varied between products. Modelling with partial least squares regression showed no overall relationship between total antioxidants and lipid data, but certain individual antioxidants showed a relationship with specific lipid fractions.     

天然抗氧化剂抑制油脂氧化的研究进展

油脂氧化是食品工业中经常遇到、严重影响食品品质的主要问题之一.虽然应用各类人工合成抗氧化剂在抑制食品中脂肪氧化的问题上取得了比较好的效果,但是这一类抗氧化剂会带来食品安全问题.深入研究和推广应用天然抗氧化剂是同时解决脂肪氧化和食品安全问题的重要途径.     

Effect of starter culture on proteolytic changes during processing of fermented beef sausages

Fermented beef sausages inoculated with four different starter cultures (Pediococcus acidilactici,Lactobacillus curvatus, Lactobacillus sake, or Streptomyces griseus) were evaluated for proteolysis during process stages (prefermentation, fermentation, drying and heating). Increases (p ? 0.05) in the nonprotein nitrogen (NPN) fraction were found at sequential stages of processing, while starter cultures had no major effects on NPN content. Concentrations of most free amino acids increased (p ? 0.05) during fermentation and drying, and culture effects were found for differences among concentrations of some individual free amino acids. From SDS–PAGE analysis of sarcoplasmic and myofibrillar protein fractions after fermentation and drying, myosin heavy and light chains, actin and troponin were degraded during processing. However, starter culture effects were absent from SDS–PAGE protein patterns.     

发酵剂对熏马肠脂肪氧化的影响

通过对熏马肠发酵成熟过程中的过氧化值、硫代巴比妥酸值、双烯值、脂肪氧合酶活力(LOX)、超氧化物歧化酶活力(SOD)和过氧化氢酶活力(CAT)等指标的测定,研究发酵剂对熏马肠发酵成熟过程中的脂质氧化、氧化酶和抗氧化酶活力的影响。结果表明:与对照组相比较,发酵剂可以显著抑制脂质氧化和LOX活力,且显著提高SOD和CAT活力。通过相关性分析表明,发酵剂组的LOX活力与过氧化值、硫代巴比妥酸值和双烯值这3个氧化指标呈不显著负相关,相关系数为0.089~0.427。SOD和CAT活力与3个氧化指标呈显著、极显著负相关,相关系数为0.684~0.970。     

Effect of processing conditions on proteolysis and taste of dry-cured sausages

 This paper deals with the influence of industrial practices such as use of starters (Lactobacillus sake and Staphylococcus carnosus), preripening (3 days at 5°C) and drying temperatures (8 and 16°C) on proteolysis, ammonia production and the taste of “salchichón”, a traditional Spanish dry-cured sausage lacking surface mould. pH dropped more sharply in the presence of a starter and at a high drying temperature (16°C); preripening did not affect the pH. The highest value for non-protein nitrogen (NPN), 16% of total nitrogen, was observed to occur in samples with the lowest pH (4.7–4.8). Total volatile basic nitrogen (TVBN) increased during drying due to the deaminase activity of internal microbial flora, which was not great (0.5–1.0% of total nitrogen) enough to affect the pH, and significantly in samples showing a larger decrease of pH. The greater proteolysis in samples with starter did not affect the assessors’ taste preference. Assessors clearly preferred those samples without starter that were dried at low temperature (8°C); however, samples with starter showed excellent commercial appearance since they dried more homogeneously. An equilibrium point must be found between acid production and taste. Received: 12 February 1996/Revised version: 24 May 1996     

Yeast populations on Spanish fermented sausages

Yeast populations on 24 lots of Spanish fermented sausages, made by four factories (F1, F2 and F4, artisanal; F3, industrial) were investigated throughout manufacture and the influence of different variables evaluated. In addition, 41 yeast strains were identified at the species level using two miniaturised systems: ATB32C (API System) and Vitek Yeast Biochemical Card (Vitek YBC). Levels of yeasts found in the sausage mixture (mean counts around 4 log units/g) were similar to those described by other authors. In sausages from factories F1 and F2, a further increase was noted, reaching 5.5 log units/g after fermentation. Counts subsequently decreased to 3.6 and 5 log units/g, respectively. In sausages from factories F3 and F4, decreasing counts were observed from the beginning, particularly in sausages from F3, where yeasts were almost absent in the finished product. Type of manufacture and sausage diameter, were the variables most influencing yeast counts. Debaryomyces hansenii (teleomorph of C. famata) was the dominant species, being found at all stages of manufacture. Trichosporon ovoides (formerly T. beigelii), Yarrowia lipolytica (perfect form of C. lipolytica), C. intermedia/curvata, C. parapsilosis, C. zeylanoides and Citeromyces matritensis (teleomorph of C. globosa) were also present. Direct identification was possible only with 50% of the total of strains investigated, although a higher number of strains was identified using the API than the Vitek YBC system.     

Effect of processing conditions on proteolysis and taste of dry-cured sausages

 This paper deals with the influence of industrial practices such as use of starters (Lactobacillus sake and Staphylococcus carnosus), preripening (3 days at 5°C) and drying temperatures (8 and 16°C) on proteolysis, ammonia production and the taste of “salchichón”, a traditional Spanish dry-cured sausage lacking surface mould. pH dropped more sharply in the presence of a starter and at a high drying temperature (16°C); preripening did not affect the pH. The highest value for non-protein nitrogen (NPN), 16% of total nitrogen, was observed to occur in samples with the lowest pH (4.7–4.8). Total volatile basic nitrogen (TVBN) increased during drying due to the deaminase activity of internal microbial flora, which was not great (0.5–1.0% of total nitrogen) enough to affect the pH, and significantly in samples showing a larger decrease of pH. The greater proteolysis in samples with starter did not affect the assessors’ taste preference. Assessors clearly preferred those samples without starter that were dried at low temperature (8°C); however, samples with starter showed excellent commercial appearance since they dried more homogeneously. An equilibrium point must be found between acid production and taste. Received: 12 February 1996/Revised version: 24 May 1996     

Lipolysis in dry-cured ham: Influence of salt content and processing conditions

Fatty acid composition of neutral lipids (NLs), polar lipids (PLs) and free fatty acids (FFA) from the intramuscular fat of Semimembranosus and Biceps femoris muscles was analysed in 46 Iberian dry-cured hams processed with different amounts of salt (6% high salt batch – HS vs. 3% low salt batch – LS w/w) and different processing systems (traditional – T vs. modified – M).

Total amounts of saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids in NLs decreased in similar proportions during processing of the hams as well as SFA, MUFA and PUFA in the PL fraction, whereas the amounts of SFA, MUFA and PUFA of FFAs significantly increased in Semimembranosus and Biceps femoris muscles. The amount of total fatty acids (TFA), from NLs and PLs, decreased in both muscles throughout the processing. Such a decline was more intense in HS hams than in LS ones, which could be a sign of a promoting effect of sodium chloride on lipolysis. However, the increase in FFA content throughout processing was not more intense in HS hams. Processing conditions studied in this work did not affect the changes in the fatty acid content of each fraction.