End Of Ripening Research Articles

Description of Ewiss cheese, a new ewe milk cheese processed by Swiss cheese manufacturing techniques: Microbiological, physicochemical, and sensory aspects

Typically, Swiss-type cheese is made from cow milk. However, in the present work an attempt to expand the sheep supply chain and product offering in this field was made by developing a new type of cheese using Swiss-type cheese technology. The cheese was manufactured under industrial conditions, and fermentations were carried out using freeze-dried commercial starters that are traditionally used in the production of Swiss cheese. Two experimental "Ewiss cheese" (EC) products were produced using raw milk (RM) and pasteurized milk (PM), respectively. Fourteen microbial groups were investigated by plate counts from curd until ripened cheeses. According to microbiological analyses, no statistically significant differences were found between the 2 productions with respect to the group of lactic acid bacteria (LAB). The curds were mainly characterized by mesophilic LAB cocci (7.45 log10 cfu/g in RM-EC and 7.33 log10 cfu/g in PM-EC). However, at the end of the ripening period (9 mo), the cheeses exhibited a higher presence of mesophilic LAB rods. Undesired microbiological groups were found only in the curd of raw milk cheese in the range of 104 to 105 cfu/g, but they were reaching undetectable levels by plate count in the cheese at the end of ripening. The RM-EC and PM-EC were characterized by 76% and 68% of DM, respectively. These cheeses contained 29.30% and 34.36% of protein, and 51.31% and 50.38% of fat, respectively. Textural analysis showed differences in terms of hardness, chewiness, and gumminess between the experimental cheeses and Swiss cheese sold on the market. These differences could be attributed to the higher protein content of ewe milk. The main fatty acids in the cheeses were palmitic acid, myristic acid, oleic acid, and capric acid. Among the organic acids, RM-EC had higher concentrations of lactic acid, whereas PM-EC was higher in propionic acid. The ewe cheeses emitted 46 volatile compounds, including acids, aldehydes, ketones, esters, alcohols, and other compounds. The PM-EC was characterized by the main compounds of Swiss-type cheese: acetic acid, butyric acid, ethyl butyrate, ethyl caproate, propanoic acid, and tetramethylpyrazine. Sensory evaluation showed that the new dairy products were generally appreciated, and PM-EC was the most preferred by the judges. This research has enabled the development of new ewe milk products, which could stimulate the valorization of a sector that has been long neglected and still has a large margin of improvement.

Investigating the effect of Persian gum on physicochemical, textural and rheological characteristics of UF white brined cheese during ripening

In this research, the effect of Persian gum at concentrations of 0, 0.03%, 0.05%, and 0.1% on syneresis, textural, and rheological properties of UF white brined cheese was investigated during ripening on days 3, 45, and 90. According to the results, the use of Persian gum led to a reduction of 26% to 44% in syneresis of samples containing gum compared to the control at the end of ripening. The increase in gum concentration resulted in a significant decrease (p ≤ 0.05) in syneresis, hardness, cohesiveness, elastic modulus, and viscous modulus of the cheeses, while their springiness showed a significant increase (p ≤ 0.05). Samples containing Persian gum exhibited the highest values of hardness and elastic and viscous moduli on day 45 of ripening, while cohesiveness and springiness showed a decreasing trend during ripening. Ultimately, the utilization of Persian gum resulted in increased production yield and improved texture of the produced cheese.

Sheep's Second Cheese Whey Edible Coatings with Oregano and Clary Sage Essential Oils Used as Sustainable Packaging Material in Cheese.

Sheep's second cheese whey (SCW), the by-product resulting from whey cheese production, was used as a component of cheese coatings containing oregano (Origanum compactum) and clary sage (Salvia sclarea) essential oils (EOs). SCW powder was obtained by the ultrafiltration/diafiltration of SCW followed by reverse osmosis and freeze drying. The coatings were produced with a mixture of SCW and whey protein isolate (WPI) using glycerol as plasticizer. Model cheeses were produced with cow´s milk and those containing SCW:WPI coatings; those with and without EOs were compared to controls without coating and with a commercial coating containing natamycin. At the end of ripening (28 days), the cheeses containing EOs presented higher water activity (ca. 0.930) and moisture content, as well as lower titratable acidity. Concerning color parameters, significant differences were also observed between products and as a result of ripening time. However, the use of SCW:WPI coatings did not significantly influence the color parameters at the end of ripening. Regarding texture parameters, the cheeses containing SCW:WPI coatings presented significantly lower values for hardness, chewiness, and gumminess. Significant differences were also observed for all microbial groups evaluated either between products and as a result of ripening time. In all cases, lactobacilli and lactococci counts surpassed log 7-8 CFU/g, while the counts of yeasts and molds increased steadily from ca. log 3 to log 6 CFU/g. The lowest counts of yeasts and molds were observed in the samples containing natamycin, but nonsignificant differences between products were observed. In conclusion, SCW:WPI cheese coatings can successfully substitute commercial coatings with the advantage of being edible packaging materials manufactured with by-products.

Application of multi-functional lactic acid bacteria strains in a pilot scale feta cheese production.

Feta cheese is the most recognized Greek Protected Designation of Origin (PDO) product in the world. The addition of selected autochthonous lactic acid bacteria (LAB) strains to cheese milk as adjunct cultures is gaining more attention, since they can impact the nutritional, technological and sensory properties of cheeses, as well as improve the safety of the product. The aim of this study was to produce Feta cheese with enhanced quality and safety, and distinctive organoleptic characteristics by applying autochthonous lactic acid bacteria (LAB) with multi-functional properties as adjunct cultures. Feta cheeses were produced with the commercial lactococcal starter culture and the addition of 9 LAB strains (Lactococcus lactis SMX2 and SMX16, Levilactobacillus brevis SRX20, Lacticaseibacillus paracasei SRX10, Lactiplantibacillus plantarum FRX20 and FB1, Leuconostoc mesenteroides FMX3, FMX11, and FRX4, isolated from artisanal Greek cheeses) in different combinations to produce 13 cheese trials (12 Feta trials with the adjunct LAB isolates and the control trial). In addition, Feta cheese manufactured with FMX3 and SMX2 and control Feta cheese were artificially inoculated (4 log CFU/g) with Listeria monocytogenes (a cocktail of 4 acid or non-acid adapted strains). Cheese samples were monitored by microbiological and physicochemical analyses during ripening, and microbiological, physicochemical, molecular and sensory analyses during storage at 4°C. The results showed that after manufacture, the LAB population was ca. 9.0 log CFU/g at all samples, whereas during storage, their population declined to 6.5-7.0 log CFU/g. In the Listeria inoculated samples, Listeria was absent after 60 days (end of ripening) and after 90 days in the adjunct culture, and in the control trials, respectively. Moreover, the addition of selected strains, especially Lcb. paracasei SRX10, led to cheeses with desirable and distinctive organoleptic characteristics. Furthermore, randomly amplified polymorphic PCR (RAPD-PCR) molecular analysis confirmed that the multi-functional LAB strains were viable by the end of storage. Overall, the results of this study are promising for the use of autochthonous strains in various combinations with the commercial starter culture to satisfy industry requirements and consumer demands for traditional and high added value fermented products.

Partial Replacement of NaCl by KCl, MgCl2 and CaCl2 Chloride Salts in the Production of Sucuk: Effects on Volatile Compounds, Lipid Oxidation, Microbiological and Sensory Properties.

The effects of different chloride salt mixtures (I-control: 100% NaCl, II: 50:50-NaCl:KCl, III: 50:30:20-NaCl:KCl:MgCl2, IV: 50:30:20-NaCl:KCl:CaCl2, V: 50:30:10:10-NaCl:KCl:MgCl2:CaCl2) on the quality properties of sucuk (a dry fermented beef sausage) during ripening were investigated. Lactic acid bacteria reached 8 log cfu/g in the 3 days of fermentation in all treatments. However, salt mixtures including MgCl2 caused an increase in Micrococcus/Staphylococcus. The control group showed the lowest mean aw value at the end of ripening. The salt mixture with 20% CaCl2 showed the lowest mean pH value of 4.97. The mean TBARS value varied between 6.34 and 6.97 µmol MDA/kg but was not affected by the salt mixtures (p > 0.05). According to the results of PCA, salt mixtures I, II and III had a positive correlation in PC1, and PC1 also separated salt mixtures with CaCl2 (IV and V) from other groups. In addition, a strong positive correlation between the control and III group (50:30:20-NaCl:KCl:MgCl2) for sensory properties was determined by heatmap clustering analysis. In addition, the principal component analysis showed that the control, II, and III groups had a stronger correlation with each other for volatile compounds.

Dynamics of Microbial Communities in Nitrite-Free and Nutritionally Improved Dry Fermented Sausages

Dry fermented sausage innovation trends are linked to consumer preferences for clean label and sodium-reduced foods. This study aims to evaluate the effect of the formulation and production process temperature on the dynamics of bacterial communities in fuet-type dry fermented sausages using metataxonomics. Six fuet batches were manufactured, including formulations without and with the addition of nitrifying salts (replaced or not by pork liver auto-hydrolysate as a colouring agent), processed at 3 to 12 °C, and a partial replacement of NaCl by KCl, processed at 12 °C. Fermentation was performed spontaneously or by a starter culture. Physicochemical characterisation and culture-dependent and independent bacterial analyses were performed at day 0, 4 and 12, at the end of ripening (aw < 0.90) and after storage. Temperature was the most important factor determining the change in pH, aw and lactic acid bacteria levels while the presence of a starter culture promoted a pH decrease. Metataxonomic analysis showed that low temperature processes and the absence of nitrifying salts allowed the growth of spoilage-related species, while sausages submitted to a mild temperature containing a starter culture and nitrifying salts showed less bacterial diversity. Liver auto-hydrolysate added putative probiotic species to the product. This study provides valuable information to manufacturers who want to innovate safely.

Volatile profile, textural and sensory properties of Diyarbakır Örgü cheese produced from sheep and cow milk of different ripening time

Diyarbakır Örgü (knitted) cheese (DOC) is a semi-fat, hard, and a pasta-filata type cheese. The objective of this study was to evaluate volatile organic compounds (VOC), and textural and sensory properties of DOC during the 120-day maturation period. For this purpose, a total of 5 different cheeses were produced as 100% sheep’s milk (C1), 100% cow’s milk (C2), 90% sheep’s milk + 10% cow’s milk (C3), 80% sheep’s milk + 20% cow’s milk (C4), and 70% sheep’s milk + 30% cow’s milk (C5). During the ripening, a total of 31 compounds, including esters (9), alcohols (5), acids (5), ketones (5), aldehydes (4), and miscellaneous (3), were identified in all cheese samples. Volatile compounds increased, both qualitatively and quantitatively, along with the increase of the percentage of sheep milk used in the cheese production increased. At the beginning of ripening, the total amount of VOC in the DOC obtained from sheep’s milk was 3.27-fold greater than that of the produced cow’s milk, while this ratio increased to 4.57 at the end of ripening. The total VOC contents of all the DOC reduced along the ripening and decreased by 53.37, 64.92, 15.53, 51.81, and 64.84% for C1, C2, C3, C4, and C5, respectively. As the amount of cow's milk used in DOC production increased, the values of all textural properties (hardness, adhesiveness, springiness, cohesiveness, gumminess, and chewiness) of the cheese increased too. On the other hand, these values decreased with the maturation (p<0.05). The rates of decrease in hardness (N), adhesiveness (N.s), springiness (cm), cohesiveness, gumminess (N), and chewiness (mJ) values of the cheese groups with the storage were C1>C3>C2>C4>C5, C4>C1>C5>C2>C3, C2>C1>C3>C4>C5, C3>C2>C1>C5>C4, C1>C4>C3>C2>C5 and C3>C4>C1>C5>C2, respectively. In terms of sensory properties (colour, texture and, taste-aroma) of the cheese mature C2, mature C1 and 30-day ripened C1 cheese samples were preferred more, respectively.

Effect of production variations on the composition, textural and microstructural properties, and volatile compounds of Turkish white cheese during ripening

Full-fat (WC1) and half-fat (WC2) Turkish white cheeses were manufactured on an industrial scale and ripened for 180 days. The objective of this study was to evaluate the variation in chemical and volatile compounds as well as the textural and microstructural characteristics during ripening of Turkish white cheese produced by different production methods from full-fat and half-fat milk. There were significant variations in the volatile compounds. For WC1 cheese, the values of hardness, cohesiveness, gumminess and chewiness values decreased towards 60 days in all cases, and then showed significant increases until the end of ripening. By contrast, the values of the different textural parameters in WC2, overall showed a tendency to decrease throughout ripening. Different effects on cheese microstructure were seen depending on milk fat content, whether or not the starter culture was added and the thermal treatment employed. Regarding volatile compounds, a total of 57 components were identified: alcohols (13), ketones (11), esters (10), acids (8), miscellaneous compounds (9) and aldehydes (6). Acids were the main components of both Turkish white cheeses. At the end of 180 days, esters and miscellaneous compounds were the highest in WC1 cheese, whereas acids, ketones and alcohols were the most abundant in WC2 cheese.

Fatty acid and amino acid profiling, antioxidant activity and other quality characteristics of vacuum packed cheddar style-yak milk cheese during ripening

This study aimed to formulate Cheddar-style cheese from standardised yak milk (casein-fat ratio: 0.7) and examined different quality parameters during 5 months ripening at 7 ± 1 °C. The chemical components viz., fat, protein, ash, and salt contents, increased significantly (p˂0.05), whereas the moisture content decreased considerably (p˂0.05) during ripening. Similarly, pH, titratable acidity [lactic acid (% by weight)], soluble protein (%), ripening index, tyrosine value (μg/g), total free fatty acids (μm/g), and peroxide value (mEq of O2/kg) increased considerably (p˂0.05) during ripening. Yeast and mould count (logCFU/g) showed a significant (p˂0.05) increase, while the coliform count (logCFU/g) were undetectable at the end of ripening. Further, cheese textural attributes and colour value (L*, a* and b*) also decreased significantly (p˂0.05). The protein hydrolysis pattern in cheese was detected using electrophoresis. The water-soluble extracts of cheese exhibited significant antioxidant activity. Palmitic (27.2%) and oleic acid (24.4%) were the prominent fatty acids detected in higher concentrations at the end of ripening. The majority of amino acids such as glutamic acid and histidine, were also retained in the cheese. The sensory ratings of cheese significantly increased as ripening proceeded, and the formulated product was acceptable for up to 120 days.

Control of Listeria monocytogenes in chicken dry-fermented sausages with bioprotective starter culture and high-pressure processing.

Listeria monocytogenes is one of the most relevant pathogens for ready-to-eat food, being a challenge for the food industry to comply with microbiological criteria. The aim of the work was to assess the behavior of L. monocytogenes in two types of chicken-based dry-fermented sausages during the fermentation and ripening, with or without a bioprotective starter culture (Latilactobacillus sakei CTC494). To complement the challenge testing approach, simulations with different predictive models were performed to better understand the role of contributing factors. The impact of post-processing strategies, such as high-pressure processing and/or corrective storage was assessed. The chicken meat was inoculated with a cocktail of three L. monocytogenes strains, mixed with other ingredients/additives and stuffed into small (snack-type) or medium (fuet-type) casings. Snack-type was fermented (22°C/3 days) and ripened (14°C/7 days), while fuet-type was ripened (13°C/16 days). At the end of ripening, HPP (600 MPa/5 min) and/or corrective storage (4 or 15°C/7 days) were applied. The suitability of HPP after fermentation was evaluated in the snack-type sausages. Pathogen growth (>3 Log10) was observed only during the fermentation of the snack type without a starter. The bioprotective starter prevented the growth of L. monocytogenes in the snack-type sausages and enhanced the inactivation (1.55 Log10) in fuet-type sausages, which could be related to the higher lactic acid production and consequent decrease of pH, but also the production of the antilisterial bacteriocin sakacin k. The gamma concept model allowed us to identify the main factors controlling the L. monocytogenes’ growth, i.e., the temperature during the early stages and aw at the end of the production process. The earlier acidification linked with the addition of starter culture made the interaction with the other factors (undissociated lactic acid, aw and temperature) to be the growth-preventing determinants. High-pressure processing only caused a significant reduction of L. monocytogenes in snack-type, which showed higher aw. The application of HPP after fermentation did not offer a relevant advantage in terms of efficacy. Corrective storage did not promote further pathogen inactivation. The findings of the work will guide the food industry to apply effective strategies (e.g., fermentation temperature and bioprotective starter cultures) to control L. monocytogenes in chicken dry-fermented sausages.

Composition and α-tocopherol content of Njeguski-type cheese made from cow, ewe and goat milk

The determination of basic composition and α-tocopherol content during ripening of Njeguski-type cheeses produced from cow, ewe and goat milk was studied. The α-tocopherol content was determined by high performance liquid chromatography (HPLC) technique with fluorescent detection. The results showed that although with the same farm practice and production technology applied, cheese composition of three types of milk differed significantly. Therefore, to standardise Njeguski cheese composition, production technology should be modified for each milk type. Additionally, the content of α-tocopherol in goat cheeses was significantly higher (P < 0.05) than the α-tocopherol content in cow and ewe cheeses: 1573 μg 100 g−1, 1039 μg 100 g−1, and 1152 μg 100 g−1, respectively, at the end of ripening.

Biocontrol of ochratoxigenic Penicillium nordicum in dry-cured fermented sausages by Debaryomyces hansenii and Staphylococcus xylosus

Penicillium nordicum is the main ochratoxin A (OTA) producing mould in dry-cured meat products. The use of autochthonous microorganisms as protective cultures is a promising strategy to control this hazard. The aim of this work was to evaluate the effect of Debaryomyces hansenii and Staphylococcus xylosus isolated from dry-cured meat products as biocontrol agents (BCAs) against P. nordicum during the ripening of dry-cured fermented sausages. The BCAs were added to the dough, and P. nordicum were inoculated on the surface after stuffing. Then, the sausages were ripened following a traditional processing. The growth of the microorganisms was determined by plate count at the beginning and at the end of ripening. To assess the implantation of BCAs in the sausages, the yeasts and staphylococci isolated from the sausages at the end of processing were identified by sequencing the 16S and 18S rRNA respectively, and they were characterized by pulsed field gel electrophoresis (PFGE) of the chromosomal DNA. OTA was quantified by UHPLC-MS/MS. BCAs were able to colonise and develop throughout the processing. Although none of the BCAs reduced the growth of P. nordicum, a OTA decrease was observed in the sausages inoculated with D. hansenii individually or combined with S. xylosus. The drop of OTA amount was particularly marked in the portions where the casing was damaged allowing the mould to grow inside the sausages. In these areas, OTA was not detected in the inoculated batches. In conclusion, D. hansenii could be proposed as BCA individually or in combination with S. xylosus for the biocontrol of OTA hazard in dry-cured fermented sausages.

Role of Melatonin in Apple Fruit during Growth and Ripening: Possible Interaction with Ethylene.

The role of melatonin during the growth and ripening of apple fruit was studied using local varieties. The evolution of the growth and ripening parameters, including fruit size and weight, firmness, color change, sugar content, and ethylene production, was different in the five varieties studied, with yellow apples (Reineta and Golden) initiating the ripening process earlier than reddish ones (Teórica, Sanroqueña, and Caguleira). Changes in the melatonin and melatonin isomer 2 contents during growth and ripening were studied in Golden apples, as was the effect of the melatonin treatment (500 µM, day 124 post-anthesis) on the apple tree. Melatonin content varied greatly, with higher value in the skin than in the flesh. In the skin, melatonin increased at day 132 post-anthesis, when ethylene synthesis started. In the flesh, melatonin levels were high at the beginning of the growth phase and at the end of ripening. Melatonin isomer 2 was also higher once the ripening started and when ethylene began to increase. The melatonin treatment significantly advanced the ethylene production and increased the fruit size, weight, sugar content, and firmness. The data suggest that melatonin stimulates fruit ripening through the induction of ethylene synthesis, while melatonin treatments before ripening improve the final fruit quality.

Integration of Multiomic Data to Characterize the Influence of Milk Fat Composition on Cantal-Type Cheese Microbiota.

A previous study identified differences in rind aspects between Cantal-type cheeses manufactured from the same skimmed milk, supplemented with cream derived either from pasture-raised cows (P) or from cows fed with maize silage (M). Using an integrated analysis of multiomic data, the present study aimed at investigating potential correlations between cream origin and metagenomic, lipidomic and volatolomic profiles of these Cantal cheeses. Fungal and bacterial communities of cheese cores and rinds were characterized using DNA metabarcoding at different ripening times. Lipidome and volatolome were obtained from the previous study at the end of ripening. Rind microbial communities, especially fungal communities, were influenced by cream origin. Among bacteria, Brachybacterium were more abundant in P-derived cheeses than in M-derived cheeses after 90 and 150 days of ripening. Sporendonema casei, a yeast added as a ripening starter during Cantal manufacture, which contributes to rind typical aspect, had a lower relative abundance in P-derived cheeses after 150 days of ripening. Relative abundance of this fungus was highly negatively correlated with concentrations of C18 polyunsaturated fatty acids and to concentrations of particular volatile organic compounds, including 1-pentanol and 3-methyl-2-pentanol. Overall, these results evidenced original interactions between milk fat composition and the development of fungal communities in cheeses.

Inoculation of Lactobacillus sakei on Quality Traits of Dry Fermented Sausages.

In this study, fermented sausage prepared by inoculating different strains of Lactobacillus sakei was assessed for their physiochemical, microbiological, and textural characteristics during fermentation and ripening. Five treatments were prepared: Control (commercial starter culture, C), L. sakei Korean Collection for Type Cultures (KCTC)-3802 (S1), L. sakei KCTC-3598 (S2), L. sakei KCTC-5053 (S3), and L. sakei KCTC-3603 (S4). The different strains of L. sakei did not show substantial differences (P>0.05) in pH values for dry fermented sausages at the end of the ripening period. Water activity (aw) values for all treatments were below 0.85 (P<0.05). Total viable count at the end of the study decreased in all L. sakei starter culture inoculated fermented sausages as S3> S2> S1> S4. High values of lactic acid bacteria (LAB) count and hardness were observed in the S2 batch as compared to other L. sakei inoculated treatments at the end of ripening (21st day). S3 inoculated with L. sakei strain exhibited significantly (P<0.05) higher value of a* (redness). A significant difference (P<0.05) in thiobarbituric acid reactive substances was exhibited in the following order: S4> S2> S1> S3> C. This study suggests that inoculation of S3 (L. sakei KCTC-5053) strain can improve the red color and reduce lipid oxidation while S2 enhances better microbiological quality as LAB. Incorporation of S3 and S2 strains accordingly can be helpful to enhance the quality of dry fermented sausages.

Effects of Allium mongolicum Regel and its extracts on the quality of fermented mutton sausages.

The study aimed to evaluate the effects of Allium mongolicum Regel (AMR) and its water‐ and fat‐soluble extracts on the quality of fermented mutton sausages. Sausages were produced with mutton and fat. Four treatments: CO, without Allium mongolicum Regel and its extracts, used as control; AMR with Allium mongolicum Regel; AWE with water‐soluble extract of Allium mongolicum Regel; and AFE with liposoluble extract from Allium mongolicum Regel, were produced and analyzed for pH, water activity (a w), free amino acids, fatty acids, and volatiles were, respectively, in fermented mutton sausages during processing (0, 2, 5, and 7 days). The results showed that the pH values of the liposoluble extract from Allium mongolicum Regel (AFE), respectively, are lower than that of sample CO at the end of fermentation and ripening. The a w in all group of sausages significantly dropped to 0.88 at the end of ripening (Day 7). Adding Allium mongolicum Regel and its water‐soluble extract can improve the serine (SER) content of fermented mutton sausage. The contents of five essential amino acids (EAA) were added when adding Allium mongolicum Regel and its fat‐soluble extract. The total fatty acid (TFA) in the treatments increased during drying and ripening. The addition of Allium mongolicum Regel and its extract can increase the content of volatile flavor substances such as 3‐hydroxy‐2‐butanone, 3‐methylbutyraldehyde, hexanal, octanal, and nonanal at the later stage of maturity, so as to improve the flavor substances in fermented mutton sausage. Water‐soluble extract of Allium mongolicum Regel (AWE) and AFE treatments had more intense flavor at the end of ripening (Day 7). The flavor of fermented mutton sausage can be improved by adding Allium mongolicum Regel and its extracts into fermented mutton sausage.

Allelic variations in the tomato carotenoid pathway lead to pleiotropic effects on fruit ripening and nutritional quality

The accumulation of carotenoids is one of the main factors that determine the quality of tomato fruit. Variations in carotenoid biosynthesis genes found in some known tomato mutants such as yellow flesh (r), tangerine (t), Beta carotene (B) and Delta carotene (Del) alter the accumulation of carotenoids and lead to fruits with colors other than red at the end of ripening. Here, we used near-isogenic tomato lines carrying these allelic variations with the aim to compare their effect on fruit ripening and on the main quality parameters in a single genetic background (Micro Tom). Fruits were harvest in the mature green stage and monitored until the red ripe stage at 23 °C. Interestingly, besides the alteration of the carotenoid profile we also observed pleiotropic effects on fruit ripening. Fruit with loss of function of the PSY1 enzyme (r) had earlier and enhanced ethylene production, as well as accelerated fruit pigmentation. Another loss of function mutant, with reduced activity of the CRTISO enzyme (t), led to reduced ascorbic acid content and delayed fruit pigmentation. Fruit carrying gain of function in the activity of β-cyclase (B) and ε-cyclase (Del) enzymes showed thicker cuticle and enhanced ethylene production, respectively. We also observed that the presence of lycopene isomers and other carotenoid isoforms increased the antioxidant capacity of fruit to a higher extent when compared to the accumulation of a single major carotenoid. Together, these results suggest the involvement of carotenoids in events that regulate ripening and tomato fruit quality, and provide bases for the modification of their accumulation to obtain fruits with different quality and nutritional composition.

Changes in the chemical and sensory profile of ripened Italian salami following the addition of different microbial starters

In this work, Italian salami were produced using microbial starters (Pediococcus pentosaceus, Lactobacillus sakei, and Staphylococcus xylosus) and compared to a control sample (without starter). Metabolomics in combination with microbiological and sensory analyses were used to investigate the overall quality. Samples were analyzed immediately after stuffing, following 7, 30, and 45 days of ripening. Each microbial starter imposed distinctive metabolomic signatures at the end of ripening. The accumulated discriminant compounds were mainly related to lipid oxidation (including hydroxy- and epoxy derivatives of fatty acids) following the inoculation with L. sakei. However, the inoculation with P. pentosaceus resulted in the accumulation of γ-glutamyl peptides, compounds driving a kokumi-related taste. Noteworthy, our findings supported the involvement of the chemical compounds profiled in the definition of final taste and aroma. This information paves the way towards the definition of more objective and tailored starters-related flavours enhancement approaches in the sector of cured meat.

Influence of the Breed of Sheep on the Characteristics of Zamorano Cheese

This work aimed to study the effects of using ewe’s milk from Churra, Assaf, or both breeds on the physicochemical and sensory characteristics of Zamorano cheese at the end of ripening. Zamorano cheese is a hard variety with protected designation of origin (PDO) produced in the province of Zamora (Spain) with raw or pasteurized ewe’s milk. Five batches of Zamorano cheese were produced with pasteurized ewe’s milk. One batch was elaborated using milk from the Churra breed, the other using milk from the Assaf breed, and the remaining three employed milk mixtures of Churra and Assaf breeds in the proportions 75:25, 50:50 and, 25:75, respectively. Cheeses made with a higher proportion of Churra milk showed a predominance of hydrophilic peptides, while hydrophobic peptides predominated in cheeses with a greater percentage of milk from the Assaf breed. The largest content of most free amino acids was found in cheeses produced with the highest percentage of Churra milk. These cheeses presented the highest values for fat acidity index and free fatty acids content and showed greater elasticity and adhesiveness, as well as lower granularity and hardness. In the sensory evaluation, aftertaste and persistence were higher in these cheeses, being scored with the best overall values.

Prevalence and fingerprinting of lactic acid bacteria community during 180 days of ripening in traditional Turkish goatskin bag Tulum cheeses produced in the mountainous region of Karaman using culture-dependent and -independent methods

The lactic acid bacteria (LAB) prevalence and dynamics of goatskin Tulum cheese produced in mountainous region of Karaman province of Turkey throughout 180 days of ripening were investigated using culture-dependent and -independent (PCR-DGGE) methods. This study used the V3-region of the 16S rRNA gene amplification and sequencing to characterise the LAB community of this cheese. Microbial counts were variable throughout the ripening. In the culture-dependent method, Enterococcus faecium shared dominance with Enterococcus hirae species at the end of the ripening, followed by Lactobacillus plantarum species. On the other hand, Streptococcus strains were predominant at the initial stage of the ripening, while E. faecium strains were identified, as well as Enterococcus faecalis and Lactococcus garvieae strains, using molecular techniques at the end of ripening. It was inferred that using these two methods together gave more information about the biodiversity and dynamics of LAB in artisanal goatskin Tulum cheeses during ripening.