Effect of the use of autochthonous Lactobacillus curvatus, Lactobacillus plantarum and Staphylococcus xylosus strains on microbiological and biochemical properties of the Sardinian fermented sausage

In this study, a starter culture was tentatively made by testing autochthonous Lactobacillus and Staphylococcus strains, isolated from traditional ‘Salsiccia Sarda’ sausage. Three sausage-making trials were carried out using an association of Staphylococcus xylosus + Lactobacillus curvatus (A), Staphylococcus xylosus + Lactobacillus plantarum (B), and Lactobacillus plantarum alone (C). Microbiological profiles, free amino acids, biogenic amines, and free fatty acids were evaluated after 21 days of ripening. Sausages A and B showed the highest number of lactic acid bacteria that produced a rapid acidification of substrates and reduced the number of spoilage microorganisms. Sausages made with L. plantarum alone or together with S. xylosus had the highest content of free amino acids, whereas the one produced with S. xylosus + L. curvatus showed the lowest content of total biogenic amines and best acceptance score. No significant differences among samples were found as to the free fatty acids concentration.     

添加复合发酵剂对发酵猪肉干食品安全性的影响

以清酒乳酸杆菌（Lactobacillus sakei）和木糖葡萄球菌（Staphylococcus xylosus）为复合发酵剂发酵猪肉干,研究复合发酵剂对发酵猪肉干腐败微生物生长增殖、组胺积累、亚硝酸盐残留、脂质氧化及挥发性氨基氮（TVB-N）生成的影响。结果表明:接种复合发酵剂显著（p<0.05）抑制发酵过程中大肠杆菌、李斯特菌、假单胞菌和金黄色葡萄球菌等腐败微生物的生长增殖;发酵结束时,添加复合发酵剂和自然发酵组的组胺含量分别为0.32和8.85 mg/kg,亚硝酸钠残留量分别为8.95和45.6 mg/kg,硫代巴比妥酸（TBA）值分别为0.67和1.54 mg MDA/kg,TVB-N含量分别为1.23和5.25 mg/100 g。添加复合发酵剂组的组织状态、风味和色泽等感官评分均高于自然发酵组,获得了优良的感官特性。      

Effect of autochthonous starter cultures isolated from Siahmazgi cheese on physicochemical,microbiological and volatile compound profiles and sensorial attributes of sucuk,a Turkish dry-fermented sausage

The effect of adding autochthonous starter cultures isolated from Siahmazgi cheese, on the physicochemical parameters and microbial counts of sucuk was investigated during the ripening period. SPME–GC/MS was used in volatile compound analysis and a trained group of panelists carried out sensory analysis of the final product. After preliminary screening, three strains of Lactobacillus plantarum, which possess desirable technological properties, were used to prepare three starter cultures: LBP7, LBP10 and LBP14. The addition of LBP7 and LBP14 starter cultures had a significant effect (P < 0.05) on lightness, leading to higher L values compared to control sausages during the ripening period. Both LBP7 and LBP14 sausages showed higher counts of lactic acid bacteria, lower growth of Enterobacteriaceae and Gram-positive catalase-positive cocci and greatly lowered the pH value compared to control sausages throughout the ripening process. At the end of the ripening process, lactic acid bacteria counts were affected (P < 0.05) by the addition of starter culture since higher counts were observed in sausages prepared with LBP7 (9.14 log CFU/g) and LBP14 (8.96 log CFU/g) batches. The decrease of water activity during the ripening of sausages was not affected by the various starters. The texture profiles of all sausages were similar except for LBP10, which showed lower hardness and gumminess during ripening. Under the conditions of the study, volatile compounds were mainly from spices, and no marked differences were found among inoculated sausages. However, sensory evaluation revealed that most of the sensory attributes were scored higher for inoculated sausages than for the control ones. Therefore, LBP7 and LBP14 could be promising candidates for inclusion as starter cultures for the manufacture of sucuk.     

复合发酵剂对羊肉发酵香肠亚硝酸盐残留量和品质的影响

以羊肉为原料不添加发酵剂、添加市售发酵剂和复合发酵剂(植物乳杆菌与肉葡萄球菌混合发酵剂比为1∶3)采用同种工艺生产三组发酵香肠。研究三组羊肉发酵香肠发酵和干燥成熟过程中的p H、Aw、色差、亚硝酸盐(NIT)含量变化以及成品的质构特性。结果显示:发酵过程中,三组发酵香肠的p H、Aw和e值均下降,混合发酵剂组p H迅速降低为4.7,低于对照组和市售发酵剂组,其NIT含量为0.66mg/kg,低于对照组和市售发酵剂组的0.79、0.8mg/kg;成熟结束时,三组的p H和e值开始上升,混合发酵剂组的Aw下降极显著(p<0.01)快于市售发酵剂组和对照组,并且三组各项质构指标除黏聚性外均差异极显著(p<0.01),最终对照组、市售发酵剂组、混合发酵剂组发酵香肠的NIT含量分别为1.38、1.46、1.26mg/kg。整体上,混合发酵剂香肠品质优于其他两组。      

复合发酵剂对羊肉发酵香肠亚硝酸盐残留量和品质的影响

以羊肉为原料不添加发酵剂、添加市售发酵剂和复合发酵剂(植物乳杆菌与肉葡萄球菌混合发酵剂比为1∶3)采用同种工艺生产三组发酵香肠。研究三组羊肉发酵香肠发酵和干燥成熟过程中的p H、Aw、色差、亚硝酸盐(NIT)含量变化以及成品的质构特性。结果显示:发酵过程中,三组发酵香肠的p H、Aw和e值均下降,混合发酵剂组p H迅速降低为4.7,低于对照组和市售发酵剂组,其NIT含量为0.66mg/kg,低于对照组和市售发酵剂组的0.79、0.8mg/kg;成熟结束时,三组的p H和e值开始上升,混合发酵剂组的Aw下降极显著(p0.01)快于市售发酵剂组和对照组,并且三组各项质构指标除黏聚性外均差异极显著(p0.01),最终对照组、市售发酵剂组、混合发酵剂组发酵香肠的NIT含量分别为1.38、1.46、1.26mg/kg。整体上,混合发酵剂香肠品质优于其他两组。     

Effect of fat quality on sausage processing,texture, and sensory characteristics

Fresh pork sausage was manufactured to determine the effects of animal diet (unsaturated or control) and inclusion of corn oil during processing (0% and 14% fat replacement). Bologna was manufactured to investigate only diet effects. Processing, textural, sensory, visual, and storage characteristics were evaluated. Processing yield was improved 2.9 percentage units in fresh sausage but reduced 1.8 units in bologna in unsaturated compared with control diets. Break strength of fresh sausage was reduced 0.6 kg by oil inclusion. Both unsaturated fat and including oil during processing resulted in softer texture of fresh sausage, while increased unsaturation in bologna resulted in firmer or unchanged textural properties. Fresh sausage with oil was lighter colored (5.3 L* units increased) with more fat smearing. In fresh sausage, lipid oxidation remained below 1 mg/kg MDA during 12 weeks frozen storage. Overall, changes in fat quality minimally affected sausage quality, likely providing acceptable products to consumers.     

Effect of somatic cell count in goat milk on yield, sensory quality, and fatty acid profile of semisoft cheese

This study investigated the effect of somatic cell count (SCC) in goat milk on yield, free fatty acid (FFA) profile, and sensory quality of semisoft cheese. Sixty Alpine goats without evidence of clinical mastitis were assigned to 3 groups with milk SCC level of <500,000 (low), 500,000 to 1,000,000 (medium), and 1,000,000 to 1,500,000 (high) cells/mL. Thirty kilograms of goat milk with mean SCC levels of 410,000 (low), 770,000 (medium), and 1,250,000 (high) cells/mL was obtained for the manufacture of semisoft cheese for 2 consecutive weeks in 3 lactation stages. The composition of milk was analyzed and cheese yield was recorded on d 1. Cheese samples on d 1, 60, and 120 were analyzed for total sensory scores, flavor, and body and texture by a panel of 3 expert judges and were also analyzed for FFA. Results indicated that milk composition did not change when milk SCC varied from 214,000 to 1,450,000 cells/mL. Milk with higher SCC had a lower standard plate count, whereas coliform count and psychrotrophic bacteria count were not affected. However, milk components (fat, protein, lactose, casein, and total solids) among the 3 groups were similar. As a result, no significant differences in the yield of semisoft goat cheeses were detected. However, total sensory scores and body and texture scores for cheeses made from the high SCC milk were lower than those for cheeses made from the low and medium SCC milks. The difference in milk SCC levels also resulted in diverse changes in cheese texture (hardness, springiness, and so on) and FFA profiles. Individual and total FFA increased significantly during ripening, regardless the SCC levels. It is concluded that SCC in goat milk did not affect the yield of semisoft cheese but did result in inferior sensory quality of aged cheeses.     

Effect of Enterococcus faecium on microbiological,physicochemical and sensory characteristics of Greek Feta cheese

Greek Feta cheese was prepared using as adjunct starter cultures Enterococcus faecium FAIR-E 198, E. faecium FAIR-E 243, and their combination. Numbers of enterococci in the control and in the batches containing E. faecium strains as adjunct starters rapidly increased until day 15 of ripening, and then remained constant. Both E. faecium strains positively affected the counts of non-starter lactic acid bacteria (NSLAB), micrococci and coliforms, while thermophilic cocci were not influenced. Moreover. E. faecium FAIR-E 243 enhanced the growth of mesophilic cocci and thermophilic bacilli. Physicochemical characteristics, such as pH, moisture, ash, salt in moisture and fat in dry matter (FDM) were not influenced by the addition of the E. faecium strains. The most pronounced effect was observed in the case of proteolysis. Both E. faecium strains, either as sole adjunct starter or in combination, increased the proteolytic index and the free amino groups concentration, and enhanced degradation of alpha(s1)- and beta-caseins in comparison to the control. Furthermore, the reverse-phase (RP)-HPLC peptide profiles of the water-soluble nitrogen (WSN) fractions were significantly affected by the addition of enterococci. The main volatile compounds produced were ethanol, acetate, acetone, acetaldehyde, acetoin and diacetyl, with highest amounts determined for ethanol, followed by acetate. Both E. faecium strains positively affected taste, aroma, colour and structure of the full-ripened cheeses, as well as the overall sensory profile. The present work emphasizes the technological significance of E. faecium strains and supports their use as adjunct cultures in the manufacture of Feta cheese.     

Effect of saffron addition on the microbiological,physicochemical, antioxidant and sensory characteristics of yoghurt

The impact of added saffron on the characteristics of yoghurt was evaluated during storage. The fat content was lower in the saffron yoghurt. All colour variables were significantly affected by saffron and storage. From the 15th day of storage, bacterial numbers in the saffron yoghurt were higher than those of the control yoghurt. Sensory analysis data suggested that colour, odour and texture impacted consistently on the overall acceptability of the saffron yoghurt. Saffron addition significantly increased polyphenol content and antioxidant activity, providing evidence that the enrichment of natural yoghurt with saffron yields an innovative fermented product useful for supplementing antioxidant dietary intake.     

Effect of Debaryomyces spp. on aroma formation and sensory quality of dry-fermented sausages

The effect of Debaryomyces spp. used in combination with starter cultures (lactic acid bacteria and staphylococci) was studied in the development of dry-fermented sausage aroma and final sensory quality. Volatile compounds were extracted by solid-phase micro extraction and analysed by gas chromatography-mass spectrometry. A paired comparison test was done to determine which sausage was preferred. Debaryomyces spp. showed an important effect on volatile generation during ripening by inhibiting the generation of lipid oxidation products and promoting the generation of ethyl esters that contribute to proper sausage aroma. However, the amount of Debaryomyces spp. used is important because larger amounts produced high generation of acids that mask the positive effect.     

Effect of the addition of pancreatic lipase on the ripening of dry-fermented sausages - Part 2. Free fatty acids, short-chain fatty acids, carbonyls and sensory quality

The effect of the addition of nine different amounts (3–500 units) of pancreatic lipase on the composition of free fatty acids (FFA), short-chain fatty acids and carbonyls, as well as the sensory quality, has been studied on dry fermented sausages. The lipase produced a greater release of all fatty acids in relation to the control sausages. The greater the pancreatic lipase content, the higher the release of these fatty acids, the most important ones being myristic, palmitoleic and oleic acids. A lower release of linoleic acid was observed, probably because of its oxidative degradation. At the end of the ripening in all lipase-added batches, a clear increase of the carbonyl content was noticed in relation to conventional sausages. No consistent changes were observed in the short-chain fatty acid fraction. In the sensory evaluation, the highest significant differences (P < 0·01) between control sausages and lipase-added batches were observed when 60 and 90 lipase units were used. According to the chemical and sensory analyses, it can be concluded that the addition of 60 and 90 units to sausages seems to be useful to enhanced the flavour of these products.     

Effect of milk thermisation and farming system on cheese sensory profile and fatty acid composition

The effect of milk thermisation and farming system on the sensory profile and fatty acid (FA) composition of a traditional cheese under real production conditions was evaluated. Raschera Protected Designation of Origin (PDO) cheese, which is produced in North-West Italy, was chosen as a case study. Cheese samples were collected in summer and winter from dairy plants that processed raw milk (IR) or thermised milk (IT) collected from intensive farms, or raw milk (ER) collected from extensive farms. The sensory profile and FA composition of IR and IT cheese were similar. The ER summer cheeses had a lower cream odour, butter odour and aroma. They had a higher rennet, strong toasted, silage, barn, garlic, boiled vegetables, and smoked odours and aromas, a higher hazelnut odour, and tasted more bitter. The ER summer cheese also expressed a more favourable FA composition for human health, which allowed it to be distinguished among the other Raschera cheese.     

Effects of radix puerariae extracts on physicochemical and sensory quality of precooked pork sausage during cold storage

Pork sausage batter without antioxidants (control), added 0.02% BHA/BHT, added 1% radix puerariae (RP), added 2% RP, and added 4% RP were cooked and stored for 28 days at 4 °C. Pork sausage added with BHA/BHT and RP had higher moisture content and lower fat content than the control. The added RP and BHA/BHT pork sausages had lower pH values than the control after 14 d. Results showed that lightness decreased upon the addition of RP. Cooking loss was lower for the added RP samples compared to the control at 14 d. Thiobarbituric acid-reactive substance (TBARS) values decreased in the added RP sausage compared to the control. Especially, 1% RP was more effective in delaying lipid oxidation compared to the other added RP treatments. Our results suggest that precooked pork sausage with RP can enhance eating quality, as sensory panels found that sausage added with RP had better color and texture.     

Effects of slightly acidic low concentration electrolyzed water on microbiological, physicochemical, and sensory quality of fresh chicken breast meat

Anticmicrobial effect of slightly acidic low concentration electrolyzed water (SlALcEW) and strong acidic electrolyzed water (StAEW) on fresh chicken breast meat was evaluated in this study. Meat samples each of 10 ± 0.2 g in weight and 2.5 × 2.5 cm2 in size were experimentally inoculated with Listeria monocytogenes (ATCC 19115) and Salmonella Typhimurium (ATCC 14028) and subjected to dipping treatment (22 ± 2 °C for 10 min) with SlALcEW and StAEW. Shelf-life study was conducted for inoculated and noninoculated meat samples treated with SlALcEW and StAEW at storage temperatures of 5, 15, and 25 °C. Dipping treatment with electrolyzed water significantly (P < 0.05) reduced the background and inoculated pathogens compared to untreated controls. The reduction of 1.5 to 2.3 log CFU/g was achieved by SlALcEW and StAEW against background flora, L. monocytogenes and Salmonella Typhimurium. There was no significant difference (P > 0.05) between the SlALcEW and StAEW treatments efficacy. Comparing treated samples to untreated controls showed that SlALcEW and StAEW treatments extended the shelf life of chicken meat at different temperatures with marginal changes of sensory quality. Although SlALcEW and StAEW treatments showed similar antimicrobial effects but SlALcEW was more beneficial in practical application for its semineutral pH and low chlorine content. PRACTICAL APPLICATION: Food safety issues have led to development of new sanitizers to eliminate spoilage and pathogenic organisms in food. This study provides the foundation for further application of slightly acidic low concentration electrolyzed water (SlALcEW) as a sanitizing agent in meat industry. SlALcEW can be produced on site on demand and no chemicals are necessary except NaCl solution. It does not leave any residue in food due to low chlorine concentration and it is safe to handle for its semineutral pH.     

不同菌株对酸奶品质与感官特性的影响

该研究以保加利亚乳杆菌（N14）和嗜热链球菌（L16）为基础发酵菌,分别添加干酪乳杆菌（GL2）、副干酪乳杆菌（GL6）、酵母 菌（Y18）、开菲尔乳杆菌（700）构成了五种酸奶发酵剂组合,分别测定这五组酸奶的酸度、质构及感官特征,采用高效液相色谱（HPLC）法对酸奶中的苹果酸、乙酸、柠檬酸、乳酸进行定量分析,评价添加不同菌株对酸奶口感和风味的影响。结果表明,4种菌株添 加均提高了酸奶的酸度,且酸奶酸度变化趋势与第一循环硬度、弹性、胶着性相同;添加菌株GL2、700和GL6提高了酸奶中乳酸的含 量;添加菌株GL2的酸奶感官评分最高（92.55分）,在果香、蒸煮味、纸板味方面表现突出,但添加菌株GL6的酸奶的感官特征与市售 酸奶最为接近。     

Effect of replacement of fat with sesame oil and additives on rheological, microstructural, quality characteristics and fatty acid profile of cakes

Effect of replacement of fat with 25, 50, 75 and 100% sesame oil (on fat basis); 50% sesame oil, hydrocolloids and emulsifiers on the rheological, microstructural, quality characteristics and fatty acid profile of cake was studied. Addition of increasing amount of sesame oil decreased viscosity, increased specific gravity of cake batter; decreased cake volume and overall quality score. Microstructure studies showed disrupted gluten matrix. Among the two different hydrocolloids [hydroxypropylmethylcellulose (HPMC) and xanthan] and emulsifiers [glycerol monostearate (GMS) and sodium stearoyl-2-lactylate (SSL)] tried, HPMC and SSL increased the batter viscosity, decreased the specific gravity, increased the volume and overall quality score. Use of combination of HPMC and SSL improved significantly the quality characteristics of cake with 50% sesame oil in such a way that the overall quality score was higher than that of the control cake with fat. The microstructure of cake crumb with 50% sesame oil and HPMC showed a smooth structure with less number of cavities and SSL showed a continuous protein matrix. On replacing the fat with 50% sesame oil, there was a decrease in saturated fatty acids and increase in unsaturated fatty acids, particularly linoleic acid. The fatty acid profile of cake with 50% sesame oil was better than the control cake as there was 2.4 times decrease in palmitic acid content and 5.9 times increase in essential fatty acids (EFA) content.     

Changes in lipid composition and fatty acid profile of Nham,a Thai fermented pork sausage,during fermentation

Changes in lipid composition and fatty acid profile of Nham during fermentation were investigated. Total lipids of Nham were in the range 2–3%. The extracted lipid of initial Nham mix consisted mainly of triglycerides (TG), accounting for more than 75% of the total lipid, followed by phospholipids (PL) and a trace amount of diglycerides (DG) and free fatty acid (FFA). During fermentation, TG, DG and PL decreased with a concomitant increase in FFA, indicating lipolysis of Nham lipids during fermentation. Changes in fatty acids of the total lipids, non-polar and polar lipid fractions were observed during fermentation. In both total and non-polar lipid fractions, the major fatty acids found in a descending order were oleic (C18:1), linoleic (C18:2) and palmitic (C16:0) acids, which together accounted for 90% of the total fatty acids. Increases in fatty acid contents in both total and non-polar lipid fractions, were observed with a corresponding decrease in the quantity of fatty acids of phospholipids. As the fermentation proceeded, peroxide value generally increased while TBARS values decreased. Overall, lipid oxidation in Nham occurred during fermentation but did not cause the objectionable odour and taste in any Nham tested.