Influence of exopolysaccharide‐producing cultures on the volatile profile and sensory quality of low‐fat Tulum cheese during ripening

The objective of this investigation was to compare the composition and changes in the concentration of volatiles in low‐fat and full‐fat Tulum cheeses during ripening. Tulum cheese was manufactured from low‐ or full‐fat milk using exopolysaccharide (EPS)‐producing or non‐EPS‐producing starter cultures. A total of 82 volatile compounds were identified belonging to the following chemical groups: acids (seven), esters (21), ketones (14), aldehydes (six), alcohols (14) and miscellaneous compounds (20). The relative amounts of acids, alcohols and aldehydes increased in the cheeses made with EPS‐producing cultures during 90 days of ripening. Differences were found in the volatile profile of full‐fat Tulum cheese compared with the low‐fat variant, especially after 90 days of ripening. Exopolysaccharide‐producing cultures changed the volatile profile, and the EPS‐producing cultures including Streptococcus thermophilus + Lactobacillus delbrueckii subsp. bulgaricus + Lactobacillus helveticus (LF‐EPS2) produced cheese with higher levels of methyl ketones and aldehydes than the non‐EPS cultures. In the sensory analysis, full‐fat Tulum cheeses and the cheese produced with the EPS‐producing culture containing Lb. helveticus (LF‐EPS2) were preferred by the expert panel. It was concluded that the use of EPS‐producing starter cultures in the manufacture of low‐fat Tulum cheese had the potential to improve the flavour.     

Effects of fat replacement with a mixture of collagen and dietary fibre on small calibre fermented sausages

Effects of fat replacement on physicochemical, microbial and sensory properties of fermented sausages were determined after drying process and 4 weeks of storage. Fermented sausages were formulated with 20% pork back fat (control), and three reduced‐fat treatments were prepared by replacing 25%, 50%, and 75% of fat with a mixture of collagen, dietary fibre and ice (1:1:8). TBARS values of reduced‐fat treatments were significantly lower compared with control after drying (P ≤ 0.05). As fat replacing ratio increased, fat content decreased significantly (P ≤ 0.05), whereas moisture, protein and ash content increased significantly (P ≤ 0.05). There was no marked difference between the treatments in terms of microbial analysis, sensory colour, flavour, off‐flavour or overall acceptability (P > 0.05) during refrigerated storage. Therefore, replacing pork back fat with a mixture of collagen and dietary fibre in fermented sausages may contribute to reduce lipid oxidation and maintain sensory properties during storage.     

Production of squid emulsion sausages using pork skin and coconut powder mixture as fat replacers

How to improve the inferior properties of squid products is a big challenge for producers. Pork skin and coconut powder (PSCP) mixture were assessed as fat replacers in squid emulsion sausages. The modified treatment containing 100% PSCP had 62.58% less fat, 4.82% more protein and 8.79% more moisture than those of the control (P < 0.05). High PSCP concentration resulted in lower cooking loss, higher emulsion stability and better textural properties. Texture profile analysis (TPA) showed that the addition of PSCP significantly (P < 0.05) increased the hardness, cohesiveness and chewiness of the sausages. The three‐dimensional network structures of the sausages containing PSCP were more compact and homogeneous. Sensory evaluation results produced by a sensory panel comprised of 100 panellists indicated that the sausages had an excellent flavour and overall acceptability when the substitution was 60%. Therefore, pork skin and coconut powder can be used to replace the pork back fat in the squid emulsion sausage without sacrificing the quality.     

Relationship between rheological,textural and melting properties of dark chocolate as influenced by particle size distribution and composition

In dark chocolate, rheological properties during processing are influenced by particle size distribution (PSD), fat and lecithin contents with consequential effects on finished texture and melting characteristics. Multivariate regression, correlation and principal component analyses (PCA) were used to explore their interrelationships. A 4 × 3 × 2 factorial experiment was conducted with varying PSD [D ₉₀ (90% finer than this size) of 18, 25, 35 and 50 μm], fat (25, 30 and 35%) and lecithin (0.3 and 0.5%). Rheological properties (yield stress and apparent viscosity), textural properties (firmness, index of viscosity and hardness) and melting index (duration) were respectively measured using shear rate-controlled rheometer, TA.HD Plus texture analyzer and differential scanning calorimetry. The PSD, fat and lecithin contents significantly influenced all rheological, textural properties and some melting characteristics. Increasing particles sizes reduced yield stress, apparent viscosity, firmness, index of viscosity, hardness and melting index of products with greatest influence with 25% fat and 0.3% lecithin, reduced with increasing fat and lecithin contents. There were high correlation (r = 0.78–0.99) and regression coefficients (R ² = 0.59–0.99) among the rheological, textural and melting index indicating their high inter-relationships. In PCA, the rheological, textural and melting index accounted for >95% variance in the data.     

Ropy exopolysaccharide-producing Bifidobacterium longum YS108R as a starter culture for fermented milk

Bifidobacteria are generally inferior compared to traditional starter lactic acid bacteria (LAB) in terms of fermentation properties. The results of this study showed that the use of a ropy EPS producing strain Bifidobacterium longumYS108R during fermentation improved the physicochemical properties of fermented milk, including decreased whey syneresis and increased water-holding capacity and apparent viscosity, however, another non-ropy EPS producing strain B. longum C11A10B did not exert such effects. Furthermore, we found that synergistically fermented milk with YS108R and commercial starter could reduce the production of acetic acid, a metabolite of bifidobacteria, and scored better in terms of sensory evaluation, especially with regards to mouthfeel texture. Comparative genomic analysis revealed a single mutation in the protein-tyrosine kinase gene of strain YS108R, which may relate to ropy phenotype. Our results indicate that ropy-EPS producing B. longumYS108R is suitable as an adjunct culture for the manufacture of novel fermented dairy products.     

The effect of using an exopolysaccharide‐producing culture on the physicochemical properties of low‐fat and reduced‐fat Kasar cheeses

A mixed starter culture containing exopolysaccharide (EPS)‐producing strains of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was combined with Lactobacillus helveticus LH301 and used in the manufacture of low‐fat and reduced‐fat Kasar cheeses. For comparison, low‐fat (C10) and reduced‐fat (C20) cheeses were made using EPS‐producing (EPS⁺) starter strain and EPS‐non‐producing (EPS^?) starter strain. The physicochemical properties of the cheeses were assessed in terms of chemical composition, texture, microstructure and microbial content over 90 days. Cheeses made with EPS‐producing culture (EPS10 and EPS20) had lower protein contents than control cheeses with 10% and 20% fat in dry basis (C10 and C20). Scanning electron microscopy images showed that using EPS‐producing culture resulted in a less compact protein matrix and sponge‐like structure in the cheese samples. In general, cheeses made using EPS‐producing culture had lower total viable counts. This could be related to the reduced survivability of EPS‐producing cells in the cheese matrix during ripening due to autolysis ability.     

Comparison of the effect of exopolysaccharide-producing lactic acid bacteria from sourdough on dough characteristics and steamed bread quality

The use of exopolysaccharide (EPS)-producing lactic acid bacteria (LAB) is promising in sourdough fermentation. However, the knowledge of the effects of various species of LAB on steamed bread making remains limited. In this study, the effects of two LAB with high EPS-producing capacity, namely Weissella cibaria L32 and Lactobacillus brevis L17 on dough fermentation and steamed bread quality were estimated. The addition of these two LAB strains significantly increased the titratable acidity and protease activity during the dough fermentation, especially L. brevis L17. Although the in situ EPS synthesised by LAB could improve the steamed bread quality, excessive acidification of L. brevis L17 would still increase the protease activity and thus destroy its gluten network structure. As a result, the steamed bread fermented with L. brevis L17 had the lowest specific volume and hardest texture in comparison with the steamed bread fermented with W. cibaria L32 and with added EPS produced by W. cibaria L32 and L. brevis L17. These results indicated that different EPS-producing LAB exhibited distinctive dough fermentation characteristics, and the in situ EPS-producing W. cibaria L32 could improve steamed bread quality, which confirmed its potential application in steamed bread making.     

Evaluation of debittered and germinated fenugreek (Trigonella foenum graecum L.) seed flour on the chemical characteristics,biological activities,and sensory profile of fortified bread

Germination of fenugreek seed showed better nutraceutical profile as evaluated by in vivo (oral glucose tolerance and acute antihypertriglyceridemic tests) on rats and in vitro DPPH and enzyme inhibition assays (α‐glucosidase, lipase, and lipoxygenase). Attempts were made to develop debittered and germinated fenugreek seed flour (DGFSF) by soaking in acesulfame (0.25%, 8 hr), curd (1:1 in water, 8 hr) and sucrose (5%, 8 hr) solution at 1:4 (wt/vol) ratio for debittering and then germinated, of which curd showed the maximum extent of debittering. The effect of substitution of wheat flour with 5, 10, 15, and 20% (wt/wt) of DGFSF on chemical characteristics and sensory properties was investigated; 10% fortified bread was organoleptically acceptable and had enhanced protein and fiber contents. Fortification increased the bulk density and crumb firmness, decreased the specific loaf volume, and darkened the crumb color. Glycemic index of the bread decreased with 10% DGFSF, which is indicative of desirable health benefits.

Practical applications

Fenugreek seeds are major constituent of Indian spices, bitter to taste and possess various medicinal properties. These seeds are an excellent source of dietary fiber and protein. Although incorporated into traditional foods, its bitterness limits its wide usage. In India, soaking and germination of seeds in water or curd was practiced traditionally since ancient days. Germination and debittering improved antioxidant activity, and various in vitro and in vivo bioactivities. Incorporation of debittered flour improved the polyphenolic, protein, and dietary fiber contents in bread which in turn demonstrated reduced rate of in vitro starch digestibility or lower glycemic index     

Sensory and nutritional attributes of fibre-enriched pasta

The objective of this study was to evaluate the impact that the incorporation of resistant starch type II (RSII), resistant starch type IV (RSIV) and oat bran (OB) have on sensory and nutritional quality of pasta. RSII, RSIV and OB were incorporated into recipes in four proportions (w/w): 2.5, 5.0, 7.5, and 10.0 g/100 g. Resistant, digestible and total starch were measured in cooked pasta. An in vitro digestion and sensory analysis of pasta were performed in order to estimate glycemic index. Results showed that both, the type and amount of added fibre influence nutritional quality of pasta. Incorporation of RSII into pasta formulation generates an additional quantity of resistant starch content in cooked pasta. Differences in in vitro digestibility of pasta can be appreciated. RSIV presented the greatest effect on total starch hydrolysis. The lower glycemic index was obtained with addition of RSIV and RSII at 7.5 g/100 g and 10.0 g/100 g. Sensory analysis showed high scores for overall acceptability for Control, RSII and RSIV samples. Results suggest that by using insoluble fibre it is possible to enhance the nutritional quality of pasta, without affecting its sensory properties negatively.     

Effects of rice bran on sensory and physico-chemical properties of emulsified pork meatballs

Four kinds of bran, which are milled from important rice cultivators in Taiwan, have high contents of dietary fiber, fat and protein. The use of rice bran in Kung-wan, an emulsified pork meatball, was investigated. It was found that protein and fat contents, and white index of meatballs decreased as the amount of bran increased. A texture profile analysis (TPA) also indicated the hardness, gumminess and chewiness of the Kung-wan decreased. The sensory scores of taste, texture and overall acceptability of meatballs with less than 10% added bran showed no significant difference from those for meatballs without bran. However, the added amount of 15% enriched meatballs resulted in inferior sensory scores. The bran’s particle size profoundly affected the sensory and physico-chemical properties of the meat products. Meatballs enriched with smaller bran particles possessed higher TPA indices and sensory scores than those added with larger ones. No significant differences in proximate composition, cooking yield, color and sensory quality were found among emulsified meatballs enriched with four different kinds of bran. Conclusively, the suitable amount of rice bran that should be added to emulsified pork meatballs was less than 10% and a smaller particle size would result in better quality.     

The effect of cheese maturity on selected properties of processed cheese without traditional emulsifying agents

The aim of this work was to compare selected properties (hardness, cohesiveness, adhesiveness, characteristics of fat globules, pH, meltability and sensory characteristics – homogeneity, rigidity and flavour) of processed cheeses (dry matter content 40 g/100 g; fat in dry matter content 50 g/100 g) made with traditional emulsifying salts (sodium salts of phosphates) and products in which the traditional emulsifying salts were replaced with 1 g/100 g κ-carrageenan. The development of the above-mentioned properties was studied in dependence on the maturity level of cheese (raw material; 1–16 weeks' maturity). The samples made without the use of traditional emulsifying salts were nearly five times as hard as the products with phosphates regardless of the maturity level of cheese. In both types of samples, hardness was decreasing and adhesiveness was rising with the increasing maturity level of cheese. Meltability of the samples without traditional emulsifying salts was very low and remained practically unchanged with the increasing maturity level of cheese. On the other hand, in the processed cheeses with phosphates, meltability was increasing with the rising maturity level of cheese.     

Technological,rheological and sensory characterizations of a yogurt containing an exopolysaccharide extract from Lactobacillus fermentum Lf2, a new food additive

Lactobacillus fermentum Lf2, an autochthonous strain isolated as a non starter culture in Cremoso cheese, produces high EPS levels (~ 1 g/L) in optimized conditions (SDM broth, pH 6.0, 30 °C, 72 h). Technological (texture profile and rheological analysis) and sensory properties of non-fat yogurts with 300 and 600 mg EPS/L were studied at 3 and 25 days after manufacture. Yogurts with different EPS concentrations showed higher hardness values than the control group at both periods of time, being the only significant difference that remained stable during time. The consistency index was also higher for the treated samples at both times evaluated, being significantly different for samples with 300 mg/L of EPS extract, while the flow behavior index was lower for EPS-added yogurts. The thixotropic index was lower (P < 0.05) for samples with the highest EPS extract concentration at the end of the storage time. Regarding the sensory analysis, those yogurts with 600 mg/L of EPS extract presented the highest values of consistency at 3 days of storage. No considerable differences for defects (milk powder, acid, bitter and cooked milk flavors) were perceived between treated and control samples at both times evaluated. Syneresis was also studied and samples with 600 mg/L of EPS extract presented the lowest syneresis values at 25 days of storage, which considerably decreased with the time of storage.In conclusion, the EPS from L. fermentum Lf2, used as an additive, provided yogurt with creamy consistency and increased hardness, without the presence of unwanted defects and improving the water holding capacity of the product. All the analysis done showed the potential of this extract to be used as a technofunctional natural ingredient, and it should be considered its positive impact on health, according to previous studies.     

Characterization of the Bread Made with Durum Wheat Semolina Rendered Gluten Free by Sourdough Biotechnology in Comparison with Commercial Gluten‐Free Products

Durum wheat semolina was fermented with sourdough lactic acid bacteria and fungal proteases aiming at a complete gluten hydrolysis. The gluten‐free (GF) semolina, added with naturally GF ingredients and structuring agents, was used to produce bread (rendered GF bread; rGFB) at industrial level. An integrated approach including the characterization of the main chemical, nutritional, structural, and sensory features was used to compare rGFB to a gluten‐containing bread and to 5 commercial naturally GF breads. High‐performance liquid chromatography was used for free amino acids (FAAs), organic acids, and ethanol analysis. A methanolic extract was used for determining total phenols and antioxidant activity. The bread characterization also included the analysis of dietary fibers, mycotoxins, vitamins, and heavy metals. Beyond chemical analysis, nutritional profile was evaluated considering the in vitro protein digestibility and the predicted glycemic index, while the instrumental texture profile analysis was performed to investigate the structure and the physical/mechanical properties of the baked goods. Beyond the huge potential of market expansion, the main advantages of durum wheat semolina rendered GF can be resumed in the high availability of FAAs, the high protein digestibility, the low starch hydrolysis index, and the better technological properties of bread compared to the commercial GF products currently present on the market. Vitamins, minerals, and dietary fiber profiles are comparable to those of gluten‐containing wheat bread. Also the sensory profile, determined by a panel test, can be considered the most similar to those of conventional baked goods, showing all the sourdough bread classic attributes.     

Effects of high pressure level and holding time on properties of duck muscle gels containing 1% curdlan

The effect of high pressure processing (HPP) on properties of duck muscle gels (DMG) containing 1% curdlan was investigated. The application of > 300 MPa could result in the decrease of cooking loss of DMG in water binding capacity, the increase of L value and the decrease of a value and b value in color, the increase of hardness, springiness, cohesiveness and chewiness in textural parameters (P < 0.05), while the pressure-holding time had no obvious influence. Those experimental results could be attributed to the interactions among protein molecules and the interactions between protein molecules and curdlan molecules created or enhanced by HPP. Overall, the use of curdlan instead of fat and the application of HPP may provide a novel approach to achieve low-fat (< 6% fat) and low-salt (1% salt) DMG products with good properties and high yields.

Industrial relevance

To provide healthier meat foods like low-fat (< 6% fat) and low-salt (about 1% salt) duck meat products, the application of HPP might be of great interest for industrial manufacture and can yield the products bearing high water binding capacity and good textural properties.     

Physicochemical and fatty acid characteristics of stewed pork as affected by cooking method and time

This study was designed to investigate the effects of cooking on physicochemical and fatty acid characteristics of stewed pork. Pre‐fried or raw pork belly cubes were stewed for 60, 90, 120, 150 or 180 min. After cooking, proximate chemical composition, texture, sensory evaluation, lipid oxidation, fatty acid profiles and cholesterol content were determined. Prolonged cooking time resulted in higher percentages of dry matter, fat and fat loss in stewed cubes (P < 0.01), and pre‐frying also increased fat loss. Tenderness and elasticity values of texture profile analysis and sensory scores were the highest for the cubes stewed for 180 min or by pre‐frying combined with stewing for 150 min. Pre‐frying and extended cooking time significantly increased lipid oxidation (P < 0.01). Cooking modified fatty acid profiles which altered the derived cardiovascular indices, and reduced cholesterol content. Prolonged stewing improved eating quality and most nutritional values of pork belly.     

马铃薯抗性淀粉对韧性饼干品质及消化性能的控制

目的 研究马铃薯抗性淀粉对韧性饼干消化性能及品质的影响规律, 为评价和提高马铃薯抗性淀粉韧性饼干的品质奠定基础。方法 通过将马铃薯抗性淀粉作为膳食纤维成分, 按照不同比例替代面粉, 制作成韧性饼干, 对韧性饼干的延展性、色泽、感官、质构特性、表观结构等物理特性、营养成分及消化性能进行测定, 研究马铃薯抗性淀粉对韧性饼干品质及消化性能的影响。结果 随着马铃薯抗性淀粉的增加, 韧性饼干的延展性总体呈增长趋势,蛋白质和脂肪含量逐渐减少,水分和灰分含量差异不显著。在马铃薯抗性淀粉添加为20%时饼干色泽均匀,硬度、脆性和咀嚼性均较好, 感官评分最高, 为82.6分。SEM观察发现随着马铃薯抗性淀粉的添加饼干结构显示暴露在油脂外的淀粉颗粒逐渐增加。马铃薯抗性淀粉的加入降低系统中淀粉的水解速率, 进而调节饼干的体外消化率, 降低血糖指数, 添加30%马铃薯抗性淀粉时, 血糖指数为62.06, 已达到中等血糖指数。结论 适量的马铃薯抗性淀粉添加到韧性饼干中可以改善饼干品质, 随着马铃薯抗性淀粉含量的增加, 饼干血糖指数降低。为抗性淀粉饼干的开发提供理论基础。     

Sensory quality of unheated and heated Mozzarella‐style cheeses with different fat,salt and calcium levels

The current study evaluated the effects of reducing fat from 23w/w to 11w/w and salt from 1.8 to 1.0w/w on the texture profile attributes, volatile compounds and sensory characteristics of unheated and heated (95 °C) mozzarella‐style cheese after 15 and 35 days of storage at 4 °C. Reducing fat content significantly impaired sensory acceptability, mainly because of associated increases in firmness, rubberiness and chewiness, and reductions in fat flavour and cheese flavour in the unheated and heated cheeses. Reducing salt content had relatively minor effects. Reducing calcium content counteracted some of the negative sensory attributes associated with reduced‐fat cheese.     

Fat reduction in emulsion sausage using an enzyme‐modified potato starch

BACKGROUND: A heat‐stable amylase‐modified potato starch (MPS) was prepared and used as a fat replacer in reduced‐fat emulsion sausages. The effects of fat level (50, 150 and 300 g kg^?1) and MPS addition (20 and 40 g kg^?1) on energy, colour, sensory, and textural properties of emulsion sausages were investigated. RESULTS: The addition of 20 or 40 g kg^?1 of MPS in reduced‐fat sausage (50–150 g kg^?1 fat) reduced total energy (15.1–49.4%), increased lightness, but lowered redness of the products (P < 0.05). The 150 g kg^?1 or 50 g kg^?1 fat sausages containing 20 g kg^?1 MPS had a similar hardness to the 300 g kg^?1 fat control (P > 0.05). Sensory evaluation indicated that the presence of MPS in reduced‐fat sausages increased (P < 0.05) the product's tenderness. CONCLUSION: Overall, the 150 g kg^?1 fat emulsion sausages with 20 g kg^?1 MPS were comparable to the 300 g kg^?1 fat control sausage in colour, texture profile, and sensory properties, but was lower in energy, suggesting that the MPS can be used as a potential fat replacer in sausage products. Copyright © 2008 Society of Chemical Industry     

Development of a novel milk‐based fermented product fortified with wheat germ

Wheat germ (WG) was mixed with water (1:5), heated (85 °C/15 min), cooled and used to replace 0, 20, 30 and 40% (w/w) of standardised cow's milk (3% fat), supplemented with 2%(w/w) skim milk powder. Yoghurt‐like fermented products were prepared from the different formulations, stored at 7 ± 2 °C for 15 days, and analysed for chemical composition, pH, microbiological quality, texture profile (TPA), viscosity, syneresis and sensory properties. The addition of WG slurry enhanced acid development during fermentation and increased the viscosity of the fermented products. Nutritious milk‐based fermented products of acceptable composition and quality could be prepared from formulations containing 20% (w/w) WG slurry.     

Partial substitution of pork fat with canola oil in Toscana sausage

The objective of this study was to develop and evaluate the effects of pork fat substitution with canola oil in Toscana sausage. Canola oil was incorporated into the product via lipid emulsion with water and collagen. The physicochemical and sensory parameters and fatty acid profiles were evaluated in five treatments with different canola oil concentrations (0, 2.5, 5.0, 7.5 and 10.0%). The prepared sausages met the legal identity and quality standards, with no significant differences detected in the variables moisture, ash content, lipid, pH, colour and weight loss due to cooking (P > 0.05). We observed a significant increase in the linolenic fatty acid content (omega-3 series). In the sensory evaluation, a significant difference was observed only for the texture variable. Pig fat substitution with 10% canola oil in the Toscana sausage exhibited the best physicochemical properties and fatty acid profile.Industrial relevanceVegetable oils have been used in meat products as an alternative to improve their lipid profiles. The amount of fat and the lipid profiles of meat products are the most important factors for product quality and consumer health. Our understanding of the relationship between the intrinsic food quality and health is gradually increasing, and as a result, a revolution has occurred in eating habits. Therefore, an innovative product for a healthier consumer market has been created to meet the challenges of animal fat substitution on the organoleptic characteristics of Toscana sausage.