Modeling of proteolysis and lipolysis in Iranian white brine cheese

The simultaneous effects of processing variables such as ripening time (20–60 days), ripening temperature (6–10 °C), level of rennet added (1–2 g/100 kg milk) and brine concentration (8–14%, w/v) on the proteolysis, lipolysis and sensory score of Iranian white brined cheese (Feta type) were explored by the means of response surface methodology. The most important effect in proteolytical terms was produced by ripening temperature and ripening time in linear form, but level of rennet added and brine concentration were also significant at the 5% level. In terms of lipolysis, ripening time was dominant factor in both linear and quadratic forms; quadratic effect of ripening temperature was greater than its linear effect.     

Changes in biogenic amines of silver carp (Hypophthalmichthys molitrix) fillets stored at different temperatures and their relation to total volatile base nitrogen,microbiological and sensory score

BACKGROUND: Biogenic amines have received considerable attention owing to their undesirable effects in humans. There are few studies of changes in biogenic amine contents related to freshwater fish. Silver carp is an important freshwater fish species in China. This study aimed to investigate the changes in biogenic amines and their relation to total volatile base nitrogen (TVB‐N), microbiological and sensory score of silver carp fillets stored at 0, 3 and 15 °C. RESULTS: The total biogenic amine contents of all silver carp fillets (regardless of storage time and temperature) ranged from 13.05 to 318.10 mg kg^?1. Putrescine and histamine were the main biogenic amines in silver carp fillets during storage. Cadaverine was only detected after 12 days at 3 °C and after 2 days at 15 °C. Spermidine and spermine contents increased during the early storage period and then slightly decreased. CONCLUSION: Low temperature could control the quality of silver carp fillets by inhibiting the contents of biogenic amines. Putrescine showed significant correlation with TVB‐N, total aerobic content, sensory score, tryptamine and phenylethylamine. Putrescine was a good quality marker of silver carp fillets in the cold chain. Copyright © 2012 Society of Chemical Industry     

Optimizing Sensorial Quality of Iranian White Brine Cheese Using Response Surface Methodology

ABSTRACT: Response surface methodology was used to evaluate the effects of processing variables, such as ripening time (20 to 60 d), ripening temperature (6 to 10°C), level of rennet added (1 to 2 g/100 kg milk), and brine concentration (8% to 14%, w/v), on the sensorial quality of Iranian pickled cheese (feta type). Optimization of sensorial quality was performed by canonical analysis to derive the stationary point. Based on contour plots and canonical analysis, optimum conditions were ripening time 32 d, ripening temperature 8.3°C, level of rennet added 1.6 g/100 kg of milk, and brine concentration 11%. Predicted sensory score was 20.76 from maximum score of 25.     

Effects of heating milk and accelerating ripening of low fat Ras cheese on biogenic amines and free amino acids development

Two experiments were conducted to study the effects of heating milk and, consequently, incorporation of whey proteins into cheese curd, fat content, accelerating cheese ripening by attenuated lactobacilli, species of bacteria and method of attenuation on formation of biogenic amines and liberation of free amino acids. Total biogenic amines and total free amino acids increased as ripening period progressed in all cheese treatments. Total biogenic amines and total free amino acids decreased as the fat content was decreased. Heating of 3% fat milk up to 70°C caused a significant (p<0.05) increase in total biogenic amines and total free amino acid concentrations, while raising the temperature of heat treatment up to 75 and 80°C decreased them. However, heating of 2% fat milk up to 75°C caused a definite (p<0.05) increase in total biogenic arnines and total free amino acids; conversely raising heat treatment temperature to 80°C decreased them. These results indicate that there is a positive correlation between total biogenic amines and total free amino acids; moisture and salt contents affected the formation of biogenic amines, while incorporation of whey proteins had no significant effect on biogenic amines development. In a second experiment, addition of attenuated lactobacilli as adjunct bacteria caused a pronounced (p<0.05) increase in free amino acids and biogenic amines. Addition of either freeze- or heat-shocked Lactobacillus helviticus was more effective in promoting the build-up of biogenic amines and free amino acids in the resultant cheeses than in cheeses made with addition of freeze- or heat-shocked Lactobacillus casei, respectively. There was a positive correlation between free amino acids and biogenic amine contents. The type of bacteria and prolongation of ripening period significantly affected the development of biogenic amines. Tyramine was the highest biogenic amine followed by histamine, while spermidine was the lowest.     

Biogenic amines in vacuum-packed and non-vacuum-packed flesh of carp (Cyprinus carpio) stored at different temperatures

Samples of carp flesh (Cyprinus carpio), vacuum-and non-vacuum-packed were stored at 3 and 15 °C. Chemical, sensory and microbial qualities were measured throughout the storage time to determine the changes that took place and to evaluate the effects of both storage temperature and the means of packaging. Seven biogenic amines (putrescine, cadaverine, spermidine, spermine, histamine, tyramine and tryptamine) were determined. Putrescine and cadaverine showed the best correspondence with the sensory and microbial states of the samples. Low storage temperature had a dominant effect, resulting in low biogenic amine content and better quality of samples. The effect of vacuum-packaging was less obvious, especially in samples kept at 15 °C. Application of vacuum-packaging at 3 °C prolonged the shelf life by about 4–5 days.     

Changes in biogenic amine and polyamine contents in smear-ripened cheeses during storage

The content of eight biologically active amines in two groups of smear-ripened cheeses (unwashed-rind and washed-rind) was analysed. The biogenic amine levels were determined after storage at 5 °C in three periods of shelf lifetime: at the minimum durability date; 1 and 2 weeks after this date. The analytical procedure consisted of amine extraction from sample matrix, derivatisation with dansyl chloride and ultra-performance liquid chromatography quantification. The content of biogenic amines and polyamines significantly differed according to the technology of ripening. The cheeses unwashed during ripening had much higher contents of all observed amines and polyamines in comparison with the washed-rind cheeses. The mean content of putrescine, cadaverine and tyramine exceeded 100 mg/kg in unwashed-rind cheeses, while the other amines occurred at lower levels. The content of all detected amines was very low in washed-rind cheeses; no tryptamine, phenylethylamine and histamine were found. The effect of storage on the amine formation was not confirmed.     

Freshness and quality attributes of cold stored Atlantic bonito (Sarda sarda) gravad

Quality and safety parameters of Atlantic bonito gravad during 42 days of storage at 7 ± 1 °C were analysed using monitoring sensory quality, microbial contamination, nucleotide degradation products, biogenic amines (BA), trimethylamine (TMA) and thiobarbituric acid reactive substances (TBARS). The shelf‐life of vacuum packed Atlantic bonito gravad was found to be 28 days. Total viable count (TVC) did not exceed 6 log CFU g^?1. Malonodialdehyde (MDA) content did not surpass 10 mg kg^?1. Nine biogenic amines were detected. Histamine level at the end of the storage was 355.3 mg kg^?1. TMA increased from 53.9 to 619.1 mg kg^?1. Among indicators based on the products of nucleotide degradation, the H value is best correlated with the sensory assessment. It can be concluded that the storage temperature of bonito gravad must be below 7 °C to prevent the threat to safety and quality posed by biogenic amines, especially histamine.     

Chemical Indicators of Decomposition for Raw Surimi and Flaked Artificial Crab

Raw surimi and a surimi-derived flaked artificial crab were stored at 4°C, 10°C and 22°C until advanced decomposition occurred. The raw surimi and the flaked artificial crab remained at an acceptable level of quality based on sensory analysis for approximately 2–4 days and 6–8 days, respectively, when stored at 10°C. Both products were of acceptable quality for at least 13 days when stored at 4°C. The potentials of total volatile acids (TVA) and total volatile bases (TVB) determined by flow injection analysis, ethanol determined by head-space gas chromatography and the amines, cadaverine, putrescine, and histamine all determined by high performance liquid chromatography, were evaluated as chemical indicators of decomposition for those products. TVA and TVB appeared to have the most potential as indicators of decomposition.     

Relation of biogenic amines to microbial and sensory changes of precooked chicken meat stored aerobically and under modified atmosphere packaging at 4 °C

The formation of biogenic amines and their correlation to microflora and sensory characteristics of a precooked chicken meat product stored aerobically and under modified atmosphere packaging (MAP) (30% CO₂, 70% N₂) was studied. Putrescine was the main amine formed both in aerobically and MA-packaged chicken samples. For the rest of the biogenic amines, including tyramine, histamine, and cadaverine, a stepwise increase was recorded throughout the 23-day storage period under the above packaging conditions. Spermidine was found in higher amounts, as compared to spermine in both aerobically and MA-packaged chicken samples at 4 °C. Formation of these amines in precooked chicken stored either aerobically or under a 30% CO₂, 70% N₂ atmosphere followed an inconsistent trend during the entire storage period at 4 °C. Agmatine, β-phenyl-ethylamine, and tryptamine were not detected in precooked chicken. Of the bacterial groups monitored, lactic acid bacteria (LAB) became the dominant bacteria after day 8 of storage under MAP while LAB were the dominant population of natural microflora of precooked chicken stored both aerobically or under MAP, reaching 7.5 and 8.0 log cfu/g, respectively, on day 23 of refrigerated storage. Enterobacteriaceae populations in chicken meat were below the detection limit (<1 log cfu/g) by pour plating throughout the 23-day storage period, irrespective of packaging conditions. Based on sensory data, after ca. 8 days for the precooked chicken meat stored aerobically and after 12 days under MAP (time to reach initial decomposition stage, score of 2) the putrescine and tyramine content of chicken samples were ca. 14–19 and 1.4 mg/kg, values that may be proposed as the limit for spoilage initiation of precooked chicken meat (respective TVC for both aerobically and MA-packaged chicken meat were ca. 6.5 log cfu/g).     

The effect of ripening and storage conditions on the distribution of tyramine,putrescine and cadaverine in Edam-cheese

The aim of the work was to describe the development of selected biogenic amines (histamine, tyramine, putrescine and cadaverine) in 4 layers of Dutch-type cheese (Edam-cheese) depending on 3 ripening/storage regimes during a 98-day period. Biogenic amines were analysed by means of ion-exchange chromatography. A further goal was to identify microbial sources of biogenic amines in the material analysed. Phenotype characterization and repetitive sequence-based PCR fingerprinting were used to identify the isolated bacteria. The highest content of tyramine, putrescine and cadaverine was determined in cheeses stored in a ripening cellar at a temperature of 10 °C during the whole observation period. Lower biogenic amines content was determined in samples which were moved into a cold storage device (5 °C) after 38 days of storage in a ripening cellar (10 °C). The lowest concentrations of biogenic amines were detected in cheeses which were moved into a cold storage device (5 °C) after 23 days of storage in a ripening cellar (10 °C). During the 98-day period, histamine was not detected in any of the regimes. Within the cheeses analysed, non-starter lactic acid bacteria Lactobacillus curvatus, Lactobacillus casei/paracasei and Lactobacillus plantarum were detected as the main producers of the biogenic amines tested. In starter bacteria Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris the decarboxylase activity tested was not detected.     

Studies of levels of biogenic amines in meat samples in relation to the content of additives

The impact of meat additives on the concentration of biogenic amines and the quality of meat was studied. Fresh white and red meat samples were fortified with the following food additives: citric and lactic acids, disodium diphosphate, sodium nitrite, sodium metabisulphite, potassium sorbate, sodium chloride, ascorbic acid, α-tocopherol, propyl 3,4,5-trihydroxybenzoate (propyl gallate) and butylated hydroxyanisole. The content of spermine, spermidine, putrescine, cadaverine, histamine, tyramine, tryptamine and 2-phenylethylamine was determined by capillary isotachophoretic methods in meat samples (fresh and fortified) during four days of storage at 4°C. The results were applied to estimate the impact of the tested additives on the formation of biogenic amines in white and red meat. For all tested meats, sodium nitrite, sodium chloride and disodium diphosphate showed the best inhibition. However, cadaverine and putrescine were characterised by the biggest changes in concentration during the storage time of all the additives. Based on the presented data for the content of biogenic amines in meat samples analysed as a function of storage time and additives, we suggest that cadaverine and putrescine have a significant impact on meat quality.     

Dynamic changes of the content of biogenic amines in Chinese rice wine during the brewing process

This study examined the biogenic amine content of the brewing raw material (wheat Qu, seed starter, mash or liquid) during fermentation and during the maturation and storage process. Pre‐column derivatization and high‐performance liquid chromatography were employed to analyse the dynamic changes in biogenic amines during the Chinese rice wine brewing process. Some aliphatic amines (putrescine, cadaverine, spermine) were already found to be present in the glutinous rice and wheat Qu, but the content was below 2.88 mg/kg. None of the amines were detected in the brewing water. The biogenic amine content in the seed starter exhibited a large variation range (16.43–87.72 mg/L), which could influence the total content of biogenic amines prior to fermentation. A much more obvious increase in biogenic amines stemmed from the fermentation process, with the presence of a biogenic amine‐producing bacteria and precursor amino amines. In the first 2 days, the biogenic amine content increased sharply, followed by a slow increase over the next 4 days, and the content reached a maximum value on day 6; subsequently there was a decrease or fluctuation in the concentration. After clarification and cooking, the biogenic amine content increased significantly; however, a slight decrease was observed during storage, especially for putrescine and histamine. Putrescine and tyramine were the most prevalent amines in all of the samples. Overall, the content of biogenic amines was found to be within the safe level for human health, ranging from 54.52 to 146. 35 mg/L. Copyright © 2013 The Institute of Brewing & Distilling     

Physicochemical and sensory evolutions of the lactic goat cheese Picodon in relation to temperature and relative humidity used throughout ripening

To produce a wide variety of cheeses, it is necessary to control the ripening process. To do that, artisanal goat cheeses were ripened to evaluate the effects of temperature (10 and 14°C) and relative humidity (RH; 88 and 98%) on (1) 16 physicochemical characteristics throughout ripening and (2) 19 sensory characteristics at the end of ripening (d 12). Whatever the ripening time, the physicochemical characteristics were strongly dependent on the daily productions, which affected the sensory perception of the cheeses. Both physicochemical and sensory characteristics were strongly reliant on RH, whereas only a few of the characteristics were influenced by temperature changes. On d 12, whatever the ripening temperature, an RH increase from 88% to 98% modified many cheese characteristics (core pH, lactate consumption, underrind thickening, dry matter content, and hardness). As a result of these physicochemical properties, changes in perception were observed: the cheeses ripened under 88% RH were dry and hard compared with those ripened under 98% RH. An RH of 98% led to an acceleration of the ripening process, inducing a slightly ammonia and milky flavor and a sticky and creamy texture in the mouth. However, cheeses ripened under 14°C and 98% RH were also indicative of overripened cheeses: a temperature of 14°C induced an acceleration of the ripening process due to physicochemical modifications compared with a temperature of 10°C. Nevertheless, when the cheeses on d 0 were still very humid and soft, those ripened under 98% RH collapsed and were overripened with a liquid underrind. This study provides a means for achieving a better and more rational control of the ripening process in artisanal lactic goat cheeses.     

The influence of sonication time on the biogenic amines formation as a critical point in uncured dry-fermented beef manufacturing

In this study, the influence of sonication time on the biogenic amines formation as a critical point in uncured dry-fermented beef manufacturing was studied. Samples of musculus semimembranosus were sonicated at different times (5 and 10 min) using ultrasound cold bath (4 °C) in acid whey (US 40 kHz and acoustic power 480 W). The effect of sonication on biogenic amine (BA) formation was investigated during 93 days of ripening period. Other parameters (pH value, water activity, microbial counts) that might provide further information on the product under study were also determined. The use of ultrasound during beef marinating in acid whey has a positive effect on retarding histamine (HIS), cadaverine (CAD), tyramine (TYR) and putrescine (PUT) formation. Moreover, the sonication treatment did not inhibit the growth of lactic acid bacteria (LAB) in dry-fermented beef during the whole ripening period. The pathogen bacteria (Staphylococcus aureus, Clostridium sp., Listeria monocytogenes) were not detected in all samples neither after 31 nor after 93 days of ripening period.     

Effect of Chitosan Coating Enriched with Ergothioneine on Quality Changes of Japanese Sea Bass (Lateolabrax japonicas)

The effect of chitosan–ergothioneine coating (CHER) on the post-mortem quality and shelf life of Japanese sea bass (Lateolabrax japonicas) stored at 4?±?1 °C for 16 days was investigated. Four different treatments were used: control without coating, CH with chitosan coating, ER with 0.3 % ergothioneine immersion, and CHER with chitosan containing 0.3 % ergothioneine coating. Sea bass pH value, total volatile basic nitrogen, peroxide value, thiobarbituric acid-reactive substances, biogenic amines, color, texture profile, and microbiological and sensory qualities were measured. The results indicate that treatment with CHER coating inhibited increase of total volatile basic nitrogen, peroxide value, and TBA value; maintained tissue hardness; and reduced microorganism counts, such as Pseudomonas, compared with control treatment. The efficiency was better than that of ER or CH treatment. Furthermore, sea bass treated with chitosan–ergothioneine coating also exhibited a positive effect, causing low biogenic amine content, especially putrescine, cadaverine, and histamine. Sensory evaluation proved the efficacy of chitosan–ergothioneine coating by maintaining the overall quality of sea bass during the storage period. Our study suggests that chitosan–ergothioneine coating might be a promising candidate for maintaining sea bass quality and extending their shelf life.     

Changes in the microbiological and chemical characteristics of an artisanal Turkish white cheese during ripening

Changes in the physico-chemical and microbiological properties of artisanal Turkish White cheese were studied throughout 105 days of ripening. Total solid, fat in solid, titratable acidity, pH, salt in total solid, total nitrogen, water-soluble nitrogen, ripening index, amino acids and biogenic amines were determined. Also, the counts of lactic acid bacteria, yeast, moulds and coliforms were done. Biogenic amines in cheeses were tyramine, histamine and phenyletylamine while tryptamine was the only detected at the beginning of maturation at the low concentration. Tyramine content increased during ripening reaching, 12.36 mg/kg at 75 days. A significant correlation could not be found (P>0.05) between microorganisms and biogenic amines. Data points represent averages of three experiments.     

Effects of previous frozen storage on chemical, microbiological and sensory changes during chilled storage of Mediterranean hake (Merluccius merluccius) after thawing

The present work aimed to investigate the influence of freezing (−20 °C for 6 months) on the susceptibility of hake to chemical, microbiological and sensory spoilage once thawed and stored in ice. Thus, volatile and biogenic amines, counts of psychrotrophic and mesophilic bacteria, enterobacteria, pseudomonads and Shewanella together with sensory evaluation (of raw and cooked samples) were monitored during 14 days of iced storage in both fresh and frozen-thawed hake (Merluccius merluccius). At the beginning of ice storage, freshness parameters were equivalent in both batches (fresh and frozen-thawed hake), but different behaviour was observed during the iced storage. Overall, levels of volatile and biogenic amines increased much later and then decreased to lower values in frozen-thawed hake in accordance with the delay of microbial development in comparison with fresh hake. On the contrary, sensory spoilage occurred earlier in frozen-thawed hake. Therefore, the usual accepted or regulated limits of acceptability of chemical and microbiological parameters would not be suitable for freshness assessment of frozen-thawed hake.     

Histamine and Tyramine during Storage and Spoilage of Anchovie, Engraulis encrasicholus: Relationships with Other Fish Spoilage Indicators

The formation of biogenic amines (histamine and tyramine) during Engraulis encrasicholus storage and spoilage was studied and compared with changes of other fish spoilage indicators: trimethylamine nitrogen, volatile basic nitrogen, hypoxanthine and pH. Good correlations were observed between biogenic amines and the other indicators, at both refrigeration (4–6°C) and room temperature (18–22°C).Two trials were carried out at each temperature. Differences were observed in levels of biogenic amines as well as other indicators in experiments carried out under similar conditions.     

Modelling of proteolysis in Iranian brined cheese using proteinase‐loaded nanoliposome

In this study, Flavourzyme was encapsulated in liposomes to accelerate the ripening of Iranian white cheese. Liposomal enzyme was prepared using a modified heating method. The influence of enzyme content, ripening time and curd retention in saturated brine on proteolysis indices and sensory perception was investigated using response surface methodology. The most influential factor on proteolysis indices was ripening time, while the content of liposomal enzyme and retention time were also significant (P < 0.05). The maximum proteolysis indices and highest sensory characteristic scores were achieved by applying 0.3% w/w enzyme, ripening for 30 days and 8‐h curd retention in saturated brine.