The use of microbial transglutaminase and soy protein isolate to enhance retention of capsaicin in capsaicin-enriched layered noodles

Specialty layered noodles (LN) were prepared by sandwiching a capsaicin-enriched dough (CED) between two gastro-resistant dough layers made up of wheat flour, soy protein isolate (SPI) and microbial transglutaminase (MTG) at 0.5 (0.5MTG LN), 1.0 (1.0MTG LN) and 1.5 (1.5MYG LN) g/100 g of wheat-SPI flour. The textural, tensile and structural breakdown properties, capsaicin retention, microstructures and the sensory characteristics of cooked LN were evaluated. Compared to other LN, 1.5MTG LN exhibited the highest textural and tensile parameters, highest capsaicin retention, densest structure and was the most difficult to breakdown. The sensory quality of all LN was acceptable, even though it was the Control LN (prepared without SPI and MTG) that scored the highest acceptability. In general, increasing the level of MTG in the sandwiching dough layers of MTG LN reduced the release of capsaicin in simulated mouth, gastric and intestinal conditions, and these results could be due to increased protein cross-linking.     

Effect of storage time on sensory and instrumental properties of skim‐milk yoghurt obtained with microbial transglutaminase

Not many studies have examined changes in microbial transglutaminase (MTG) yoghurts during storage. In this work, yoghurts manufactured with skimmed milk and treated with MTG were evaluated in refrigerated storage for 35 days. Instrumental measurements showed that firmness, consistency and pH values in MTG yoghurt experienced a significant increase with the storage time. However, sensory measurements showed that MTG yoghurts were not affected significantly by storage time. Acid taste scores only increased significantly with storage time in the control samples. Microbial transglutaminase treatment showed a positive effect on textural properties and allowed syneresis to be prevented completely during storage.     

Microbial transglutaminase and caseinate as cold set binders: Influence of meat species and chilling storage

The effect of microbial transglutaminase/sodium caseinate (MTG/C) systems on meat batter characteristics (water binding and textural properties of raw and cooked products) was studied in the presence of NaCl (1.5 g/100 g) and sodium tripolyphosphate (0.5 g/100 g), and storage time (96 h at 3 °C) for three meat species (pork, chicken, lamb). Samples prepared from pork and lamb with only MTG/C (no salts) had the highest cooking loss (CL) values, about 23 and 29 g/100 g, respectively; for chicken, the CL was less than 13 g/100 g. Hardness (Hd) and chewiness (Cw) generally tended to be higher in cooked samples containing MTG/C than in samples containing only salts. Products combining salts and MTG/C had higher (P<0.05) Hd and Cw. The efficiency of the MTG/C system as a texture conditioner of cooked products varied with the meat source.     

Effect of iron fortification on microstructural,textural, and sensory characteristics of caprine milk Cheddar cheeses under different storage treatments

In this study, we manufactured 3 types of caprine milk Cheddar cheese: a control cheese (unfortified) and 2 iron-fortified cheeses, one of which used regular ferrous sulfate (RFS) and the other used large microencapsulated ferrous sulfate (LMFS). We then compared the iron recovery rates and the microstructural, textural, and sensory properties of the 3 cheeses under different storage conditions (temperature and duration). Compositional analysis included fat, protein, ash, and moisture contents. The RFS (FeSO₄·7H₂O) and LMFS (with 700- to 800-μm large particle ferrous sulfate encapsulated in nonhydrogenated vegetable fat) were added to cheese curds after whey draining and were thoroughly mixed before hooping and pressing the cheese. Three batches of each type of goat cheese were stored at 2 temperatures (4°C and ?18°C) for 0, 2, and 4 mo. We analyzed the microstructure of cheese using scanning electron microscopy and image analysis software. A sensory panel (n = 8) evaluated flavors and overall acceptability of cheeses using a 10-point intensity score. Results showed that the control, RFS, and LMFS cheeses contained 0.0162, 0.822, and 0.932 mg of Fe/g of cheese, respectively, with substantially higher iron levels in both fortified cheeses. The iron recovery rates of RFS and LMFS were 71.9 and 73.5%, respectively. Protein, fat, and ash contents (%) of RFS and LMFS cheeses were higher than those of the control. Scanning electron microscopy analyses revealed that LMFS cheese contained smaller and more elongated sharp-edged iron particles, whereas RFS cheese had larger-perimeter rectangular iron crystals. Iron-fortified cheeses generally had higher hardness and gumminess scores than the control cheese. The higher hardness in iron-fortified cheeses compared with the control may be attributed to proteolysis of the protein matrix and its binding with iron crystals during storage. Control cheese had higher sensory scores than the 2 iron-fortified cheeses, and LMFS cheese had the lowest scores for all tested sensory properties.     

Effects of chitosan coating containing lysozyme or natamycin on shelf‐life,microbial quality,and sensory properties of Halloumi cheese brined in normal and reduced salt solutions

The effects of chitosan (C) coating with or without lysozyme (L) or natamycin (N) on shelf‐life, microbial quality, and sensory properties of Halloumi cheese held at 3 °C or 25 °C in 5%, 10% or 15% (w/v) NaCl were examined. Coatings increased cheese shelf‐life by ≥ 5 days than the control when brined in 5% and 10% NaCl at 3 °C but did not affect the shelf‐life of cheese in 15% NaCl. Nonetheless, coatings reduced psychrotrophs, anaerobes, lactic acid bacteria, and yeasts and molds by 1.8 to 2.2 log in 15% brined cheese. Reductions of microbial species contaminating Halloumi cheese at 10% and 15% brine were not significantly different with CL and CN coatings throughout storage at 3 °C. Coatings did not adversely affect sensory properties of cheese. Therefore, brine concentration could be reduced to 10% for CL and CN‐coated cheeses.

Practical applications

Results support the possibility of reducing the high salt concentration in brine solution of Halloumi cheese by using a chitosan coating containing lysozyme or natamyc in which provided similar shelf‐life and microbial stability. The coatings did not adversely affect the sensory properties of cheese and can be applied by a simple step during processing which facilitates their use in the food industry.     

Biopreservation by Lactobacillus paracasei in coculture with Streptococcus thermophilus in potentially probiotic and synbiotic fresh cream cheeses

The viability of Lactobacillus paracasei and its effect on growth of the microbiota in potentially probiotic and synbiotic fresh cheeses during storage at 4 +/- 1 degree C was investigated. Three cheese-making trials (T1, T2, and T3) were prepared in quadruplicate, all supplemented with a Streptococcus thermophilus culture. L. paracasei subsp. paracasei was added to cheeses in T1 and T2, and inulin was added to cheeses in T2. Counts of L. paracasei, S. thermophilus, coliforms, Escherichia coli, Staphylococcus spp., DNase-positive Staphylococcus, and yeasts and molds were monitored during storage for up to 21 days. Viable counts of L. paracasei in probiotic (T1) and synbiotic (T2) cheeses remained above 7 log CFU/g during the entire storage period, whereas counts of S. thermophilus remained above 9.5 log CFU/g for cheeses from TI, T2, and T3. Populations of coliforms, Staphylococcus spp., and DNase-positive Staphylococcus were higher in T3 cheese and differed significantly from those in cheeses from T1 and T2 (P < 0.05). Inhibition of contaminants prevailed when both L. paracasei and S. thermophilus were present in fresh cream cheese and probably was due to acid production by both strains; bacteriocin production was not found. Addition of inulin in T2 did not impact microbial viability (P > 0.05). L. paracasei subsp. paracasei in coculture with S. thermophilus was inhibitory against microbial contaminants in fresh cream cheese with or without the addition of inulin, indicating the potential use of this combination in a probiotic and synbiotic product.     

Effect of non-meat proteins on hydration and textural properties of pork meat gels enhanced with microbial transglutaminase

The combined effect of incorporation of four non-muscle proteins, NMP (blood plasma, BP; sodium caseinate, SC; soy protein isolate, SPI; gelatin, G) at 2 g/100 g levels on hydration and textural characteristics of pork gels processed without or with 0.6 g/100 g microbial transglutaminase preparation (MTG) was investigated. Addition of SC and BP most favourably affected hydration properties and thermal stability, yielding lower cooking loss and expressible moisture for pork gels. Interactions between NMP and MTG were observed. Improvement of gel strength by addition of transglutaminase was observed for treatments containing SC and BP but not G nor soy isolate. Of the four proteins tested SC was found to be a superior substrate for MTG in enhancing textural properties of a gelled meat system. None of the tested ingredients was able to yield gel cohesiveness equivalent to the control containing 8% muscle proteins. Results of this study indicate a potential for using MTG to improve or modify the functional and textural properties of investigated food proteins (SC and BP in particular) in comminuted meat products.     

Physicochemical,microbial, and sensory evaluation of cook-chilled Korean traditional rice cake (<Emphasis Type="Italic">Backseolgi</Emphasis>) during storage via various packaging methods

Backseolgi is a Korean traditional rice cake, which is prepared by steaming the rice flour. After cook-chilling processing, backseolgi samples packaged by a modified atmosphere package (MAP), top sealing package (TSP), and linear low density-polyethylene package (LDPA; control) were evaluated in regard to microbial safety and sensory characteristics during storage. During storage at 30°C, the cell numbers of aerobic, psychrophilic, and anaerobic bacteria for the MAP sample increased to below 2 log CFU/g for 10 days, whereas the control and TSP samples increased more than 5.0 log CFU/g after 4 days. After 50 days of storage at 3°C, the cell numbers in the MAP sample were below 1.0 log CFU/g, whereas they were approximately 3.0 log CFU/g in the control and TSP samples. In the case of the sensory evaluation, the MAP sample score was above 5.0, whereas the scores of the CON and TSP samples were 1.0. As a result, MAP was identified as the most effective packaging method for increasing microbial safety while maintaining the sensory characteristics of the cook-chilled backseolgi.     

Physicochemical,textural and sensory properties of white soft cheese made from buffalo and cow milk mixtures

The physicochemical, textural and sensory properties of white soft cheeses made from three different buffalo and cow milk mixtures (100:0, 70:30 and 30:70) during 3‐month storage were studied. The increase in buffalo milk concentration resulted in increasing total cheese yield, dry matter (DM) and fat retention and fat in DM content. However, it caused reductions in moisture content, salt intake, hardness, chewiness, elasticity, sensory hardness and sensory cohesiveness of the samples. The percentage of water‐soluble nitrogen to total nitrogen increased during storage resulting in decreased fracturability, hardness (textural and sensory), cohesiveness (textural and sensory), springiness, chewiness and elasticity. The panellists evaluated the white soft cheese made with buffalo milk as the most acceptable.     

Physical,chemical, microbial,and sensory evaluation and fatty acid profiling of value-added drinking yogurt (laban) under various storage conditions

Yogurt is defined as a coagulated milk product obtained from the fermentation of lactose into lactic acid. Drinking yogurt (laban) was prepared from buffalo milk, cow milk, and a 50:50 blend (cow + buffalo milks) by adding 0.5% carboxymethyl cellulose to each of the 3 milk treatments. Samples were then refrigerated for 7, 14, and 21 d before determination of physical, microbial, and sensory parameters. Yogurt prepared from buffalo milk had higher fat and protein contents, and better taste, aroma, and overall consumer acceptability compared with laban prepared from cow milk or mixed milk. During storage, protein and total solids contents remained unchanged, whereas milk fat, color, appearance, taste, smell, texture, and overall acceptability of laban decreased in the different treatment groups. The acidity of laban increased with storage time. Bacteria, including coliforms, were not found in any treatment group during storage. In conclusion, overall acceptability of laban prepared from buffalo milk was higher than that made from cow milk or mixed milk, but increased storage time reduced the quality of laban prepared from cow, buffalo, or mixed milk.     

Evaluation of the effect of salts on chemical,structural, textural,sensory and heating properties of cheese: Contribution of conventional methods and spectral ones

ABSTRACT

Chemical composition, sensory characteristics, textural and functional properties are among the most important characteristics, which directly relates to the global quality of cheese and to consumer acceptability. A number of factors including milk composition, processing conditions and salt content, influences these properties. The past decades many investigations were performed on the possibilities to reduce salt content of cheese due to its adverse health effects, the current lifestyle and the awareness of the consumers for nutrition quality products. Due to the multiple potential effects of reducing NaCl (simple reduction or substitution) on cheese attributes, it is of utmost importance to identify and understand those effects in order to control the global quality and safety of the final product.

In the present review a collection of the different results and conclusions drawn after studying the effect of salts by conventional (e.g. wet chemistry) and instrumental (e.g. spectral) methods on chemical, structural, textural, sensory and heating properties of cheese are presented.     

Effects of natural compounds on microbial safety and sensory quality of Fior di Latte cheese, a typical Italian cheese

This work presents a preliminary study to assess the efficiency of plant essential oils as natural food preservatives in Fior di Latte cheese. Selected compounds were directly dissolved into Fior di Latte brine. Packaged Fior di Latte samples were stored at 10°C for about 6 d. The cell loads of spoilage and useful microorganisms were monitored to calculate the microbial acceptability limit. Results show that some tested compounds were not acceptable by the panel from a sensorial point of view. Most compounds did not affect the microbial acceptability limit value to a great extent, and only a few such as lemon, sage, and thyme markedly prolonged the microbial acceptability limit of the investigated fresh cheese. Moreover, the above active agents exerted an inhibitory effect on the microorganisms responsible for spoilage without affecting the dairy microflora.     

Extending the shelf life of fresh ewe’s cheese by modified atmosphere packaging

This study evaluated the effect of modified atmosphere packaging (MAP) in extending the shelf life of a fresh ewe’s cheese stored at 4 °C for 21 days. Three batches were prepared with 20, 30 or 50% CO₂ with N₂ as filler gas. MAP controlled well the microbial growth, and the best result was obtained with 50% CO₂. Pathogens were not detected in any sample. Softening of cheese was best reduced by 30% or 50% CO₂. The sensory characteristics of the cheeses markedly decreased during storage. Only the sample stored with 50% CO₂ obtained an overall score above the acceptability at 14 days.     

Proteolysis and textural properties of low‐fat ultrafiltered Feta cheese as influenced by maltodextrin

Maltodextrin was used as a fat replacer in low‐fat ultrafiltered cheese. Fat was replaced with 25% maltodextrin milk solution (w/w) in cheese at 15 and 50% (w/w). The chemical, rheological and sensory properties as well as the microstructure of the cheese samples were evaluated after storage for 2 months at 8 °C. Maltodextrin affected the chemical (pH, dry matter, fat, water‐soluble nitrogen to total nitrogen, nonprotein nitrogen to total nitrogen, total free amino acid) and rheological (mean relaxation time) properties, as well as the microstructure. In general, based on textural properties, sensory evaluation and economic aspects, the 50%‐fat‐reduced sample was selected as the best treatment.     

Konjac/gellan gum mixed gels improve the quality of reduced-fat frankfurters

Mixed gels of konjac (1%, 2%) and gellan gum (0.25%, 0.5%) were incorporated into reduced-fat (18%) frankfurters and compared with reduced-fat and high-fat (28%) controls for physicochemical, textural, sensory properties and storage stability. C28 (control at 28% fat) had the highest (P<0.05) lightness (L*) and yellowness (b*) values but the lowest redness (a*). C28 had the lowest textural hardness, shear force value and sensory firmness but highest juiciness scores. Treatments containing konjac/gellan gum mixed gels were not different from C28 in sensory overall acceptability, among them K1G5 (1% konjac/0.5% gellan gum) was numerically higher. C18 had the highest TPC (～7.8 log CFU/g) after 12 weeks of storage, followed by gum-containing treatments. In conclusion, it appears feasible to incorporate konjac/gellan gum mixed gel at current levels to reduced-fat frankfurter for acceptable sensory merits with reasonable shelf life.     

Moderately High Hydrostatic Pressure Processing to Reduce Production Costs of Shredded Cheese: Microstructure, Texture, and Sensory Properties of Shredded Milled Curd Cheddar

ABSTRACT: Short and moderate hydrostatic pressure (MHP) treatments accelerated the shredability of Cheddar cheese. Both MHP (345 MPa for 3 and 7 min) and higher pressure (483 MPa for 3 and 7 min) treatments applied to 1-d milled curd Cheddar cheese induced immediately a microstructure resembling that of ripened cheese. Unripened pressure-treated Cheddar cheese yielded shreds with visual and tactile sensory properties similar to those obtained from untreated 27-d-old Cheddar cheese. All pressure treatments reduced the presence of crumbles, increased mean shred particle length, improved length uniformity, and enhanced surface smoothness. Sensory evaluations showed that shredded samples of 1-d MHP-treated cheese and 27-d untreated cheese had similar sensory attributes. Pressure treatments did not affect mechanical properties of ripened cheese and milk protein proteolysis was not inhibited. These results showed that MHP would allow processors to shred milled curd Cheddar cheese immediately after block cooling with expected refrigerated storage savings of more than $30 US/1000 kg cheese and could simplify the handling of cheese for shredding. Shreds from unripened milled curd Cheddar cheese can thus be produced with high visual acceptability and improved tactile handling using moderate levels of hydrostatic pressure.     

Effect of whey pH at drainage on physicochemical, biochemical, microbiological, and sensory properties of Mozzarella cheese made from buffalo milk during refrigerated storage

The objective of this research was to determine the effect of drainage pH on physicochemical, biochemical, microbiological and sensory properties of Mozzarella cheese made from buffalo milk during refrigerated storage. Four vats of cheese were made at 4 different whey drainage pH (6.2, 5.9, 5.6, and 5.2). Lower drainage pH caused higher pH 4.4-soluble N and pH 4.4-soluble N:total N. Interaction of drainage pH at d 1 and 30 of storage on all soluble nitrogen fractions was significant. Degradation of caseins in samples made at a drainage pH of 6.2 was lower than that of other cheese samples. The decreasing whey drainage pH significantly increased counts of thermophilic and mesophilic lactobacilli of the samples during refrigerated storage. No coliforms or Escherichia coli were detected in the cheeses. The average sensory property scores of all cheese samples were very close, and, as expected, storage time had a negative effect on all sensory scores.