Aw Values Research Articles

Using Celery Powder in a Semi-Dry Fermented Sausage 'Heat-Treated Sucuk': Nitrosamine Formation, Lipid Oxidation, and Volatile Compounds.

This study investigated the effect of using celery powder (CP) as source of pre-converted nitrite (treatments: A: 150 mg/kg NaNO2, B: 100 mg/kg NaNO2 + CP as 50 mg/kg NaNO2 equivalent, C: 50 mg/kg NaNO2 + CP as 100 mg/kg NaNO2 equivalent, D: CP as 150 mg/kg NaNO2 equivalent) on the physicochemical and microbiological properties in heat-treated sucuk (HTS), a kind of semi-dry fermented sausage. The influence of cooking time (CT) on the nitrosamine formation in HTS with and without CP was also determined. The results indicated that the use of CP increased the pH value and decreased the aw value. Micrococcus/Staphylococcus and residual nitrite were not affected by the use of CP. TBARS value varied from 0.78 to 0.90 mg MDA/kg. CP did not affect the abundance of hexanal in HTS, however, it increased the abundance of camphene. The results of PCA showed that treatments A, B, and C had similar volatile compound profiles. CP did not affect both N-nitrosodimethylamine and N-nitrosodiethylamine, but their levels increased as the CT increased. Increased CT also resulted in increased N-nitrosopiperidine (NPIP) in all treatments, but the cooking for 1 min did not cause a significant increase in treatments A, B, and C. CP leads to a significant increase in NPIP content, especially after 3 and 5 min of cooking in HTS.

Comparative analysis of the heavy-weight floor impact noises using different types of EVA resilient materials

The present study aims to improve the floor impact noises using various shapes of EVA resilient materials in composite floor structures. In order to this, three different types of EVA resilient materials were used including flat plate, deck plate type and cavity type of EVA boards. All the composite structure consisted of PP panel, PET and EVA resilient materials with a total depth from 30mm to 40mm. Total of 9 specimens were made for floor impact sound measurements. All the floor impact sound measurements were done at the recognized testing authority using bang machine. The values of L'I,Fmax,AW were deduced from every measurements. As a result, among the various types EVA resilient materials, most high performances were drawn when cavity type of EVA resilient material was used. It was shown that the average L'I,Fmax,AW value of cavity type was 46dB while 47dB for deck plate type, 48dB for flat plate were measured in average. It can be recognized that the good performance of cavity type EVA materials is caused by the both air layer gap beneath EVA board and air cavity inside the EVA board as well as the low dynamic elastic modulus of EVA.

Improvement and quality evaluation of gluten-free cake supplemented with sweet potato flour and carrot powder

Celiac disease and wheat allergy are immune-responsive small bowel disorders that respond solely to the ingestion of gluten-fortified wheat or wheat flour. As a result, for those who are allergic to wheat flour or gluten, the primary treatment is a gluten-free or wheat-free diet. The goal of this research is to develop a gluten-free cake with sweet potato and carrot powder, as well as to examine the Proximate analysis, mineral content, physical properties, and microbiological qualities determined using standard analytical procedures. To make cakes, instead of wheat flour, a combined formulation of 80 % sweet potato flour and 20 % carrot powder, 60 % sweet potato flour and 40 % carrot powder was incorporated into the cake ingredients. Quality evaluation of sample cakes was performed by physicochemical and storage properties. The proximate analysis of the data revealed that the cakes that were created contained adequate levels of protein, fiber, and carbohydrates with percentages ranging from 8.12 to 8.25 %, 3.19–4.19 %, and 36.03 to 38.25 %, respectively. Additionally, an appreciable amount of potassium, calcium, magnesium, phosphorus, and iron have been found in gluten-free cakes. There was color to the gluten-free cakes; L*, a*, and b* ranged from 42.66 to 43.60, 10.03 to 11.21, and 21.81 to 23.28, respectively. There is an assurance of a good color property because the hue and chroma values varied from 11.74 to 25.83 and from 41.02 to 78.03, respectively. The water activity (aw) value ranged from 0.854 to 0.870, which increased from 0.879 to 0.901 during storage. Furthermore, the microbial analysis revealed that the total viable count of all samples remained within the acceptable range after 8 days of storage. The findings of this study show that carrot powder and sweet potato flour can be used to overcome the limitations of gluten-free cakes and improve their nutritional quality.

Antimicrobial Properties of Fennel By-Product Extracts and Their Potential Applications in Meat Products.

Background: Beef burgers are perishable meat products, and to extend their shelf life, EU Regulation 1129/11 permits the use of certain additives. Objectives: However, given the concerns of health-conscious consumers and the potential toxicity of synthetic substances, this study aimed to explore the use of fennel waste extracts as natural preservatives. Methods: This study characterized the bioactive compounds (phenolic content), the antioxidant activity (ABTS+ and DPPH assay), and the antimicrobial properties (against Salmonella enterica serotype Enteritidis, Escherichia coli, Staphylococcus aureus, Bacillus cereusi, and Pseudomonas aeruginosa) of different fennel waste extracts (LF, liquid fraction; SF, solid fraction and PF, pellet fraction). Additionally, the potential use of the best fennel extract was evaluated for its impact on beef burger shelf life (up to 18 days at 4 ± 1 °C) in terms of microbiological profile, pH, and activity water (aw). Results: The PF extract, which was rich in flavones, hydroxybenzoic, and hydroxycinnamic acids, demonstrated the highest antioxidant and antimicrobial activities. Microbiological analyses on beef burgers with PF identified this extract as a potential antimicrobial substance. The aw and pH values did not appear to be affected. Conclusions: In conclusion, fennel extracts could be proposed as natural compounds exploitable in beef burgers to preserve their quality and extend their shelf-life.

Estimating cation exchange capacity from hygroscopic water content change

AbstractThe existing models for estimating cation exchange capacity (CEC) from easy‐to‐measure hygroscopic water content (θh) were based on a single water activity (aw) value rather than on the processes that govern soil water vapor adsorption for a distinct aw range. Here, we present a new CEC estimation model based on θh data of 119 soils with different clay mineralogy (i.e., illitic [IL], montmorillonitic [ML], and kaolinitic [KA] samples) and organic carbon (OC) contents for the aw range from 0.23 to 0.57 (Δθ0.23–0.57) and validate its performance. Based on the hypothesis that multilayer adsorption exhibits a higher correlation with CEC than monolayer adsorption and capillary condensation, the aw range from 0.23 to 0.57 was chosen with CEC calculated as CEC = k × Δθ0.23–0.57. The performance of the new model is compared to the Arthur (2017) model and the Torrent (2015) model, which considers a single θh value. The average proportionality coefficient (k) varied with the dominant clay mineralogy of the investigated soils. For soils dominated by 2:1 clay minerals (i.e., IL and ML), the new model showed a good estimation accuracy (Nash‐Sutcliffe model efficiency [E] ≥ 0.85; root mean squared error [RMSE] ≤ 4.18 cmol(+) kg−1). The new model performed better for IL and ML samples than for KA samples, and yielded more accurate CEC estimations than the Arthur model and Torrent model for soils with 2:1 clay minerals. For soil with high OC content (>23.2 g kg−1), the new model slightly underestimated CEC (E = 0.66; RMSE = 5.87).

Biochemical and physicochemical characteristics and volatile profiles of Erzincan Tulum cheese coagulated by herb-fortified artisanal lamb rennet

The characteristics of Erzincan Tulum cheese (ETC), an artisanal ewe-milk cheese and the first cheese with the designation of origin in Türkiye, are closely related to the geographical location of production and the human factors influencing every stage of the production process. This study aims to determine the influence of different coagulants (namely, herb-fortified artisanal lamb rennet (ALR), artisanal calf rennet (ACR), and commercial calf rennet (CCR)) on the biochemical, physicochemical characteristics, and volatile compounds of ETC, produced on the Heybeli plateau of the Erzincan province. Using artisanal rennet increased total solids, fat content, and acidity while decreasing pH and aw values. The highest PTA-SN (soluble nitrogen in 5 % phosphotungstic acid, w/v) and TCA-SN (soluble nitrogen in 12 % trichloroacetic acid w/w) values at the end of the ripening period (day 150 of storage) were observed in the ALR-Cheese (ALR-C). Furthermore, this cheese exhibited the highest rate of lipolysis (P < 0.01). Electrophoretograms revealed that αs-1 and β-casein degradation rates were the most significant in ALR-C. Following the 30th day of storage, the highest counts of lactic acid bacteria (LAB) were found in ALR-C. The most rapid reduction of coliforms, E. coli, and yeast-mold was observed in this sample throughout the storage. Eighty-nine volatile compounds were identified in the samples. Particularly noteworthy, ALR-C exhibited the highest ratios of hexanoic, octanoic, and decanoic acids after 90 days of storage. Additionally, steroid compounds were exclusively detected in this sample. The findings of this research make a substantial contribution to the existing literature concerning rennet types and the aromatic profile of ETC. These aspects are crucial for further investigations to enhance the cheese's quality and safety.

ANALYSIS OF PH VALUE AND WATER ACTIVITY AS KEY SAFETY PARAMETERS FOR KULEN SAUSAGE

Active acidity (pH) and water activity (aw) were analyzed in 14 samples (K01-K14) of kulen available in markets in the Republic of North Macedonia. These samples were produced under industrial conditions by various manufacturers from R.N. Macedonia and neighboring countries in the region. The obtained pH values ranged from 4.24 to 4.97, while the aw values of the Kulen sausages ranged from 0.789 to 0.903. The pH and aw values are critical parameters for assessing the stability and safety of fermented products. According to European regulations, fermented sausages do not support the growth of L. monocytogenes under conditions of pH ≤ 5.0 and aw ≤ 0.94. All analyzed samples of kulen sausages (K01-K14) fall within this range that does not support the growth of L. monocytogenes, indicating a well-controlled technological process.

Evaluation of spray drying microencapsulation for folic acid fortification of dried rice vermicelli (Khanom Jeen)

This study evaluated spray drying (SD) microencapsulation of folic acid for physicochemical properties and its overall suitability for fortification of dried rice vermicelli. The SD microcapsules were formulated to achieve 30 µg of folic acid per 100 g of flour. The formula was homogenized into a 2% solid phase and made into a dry powder by the SD dryer, and the fortified dough was produced and dried in the final step. Fortified samples were analyzed for chemical and physical attributes, sensory evaluation, folic acid content, and stability in processing. The physical quality testing, water content, and the aw values were significantly different from controls (P < 0.05). The acid content was not significantly different (P > 0.05). Color difference, as assessed by a colorimeter, was significant (P < 0.05). In the mixing, extrusion, and first and second washing steps, the coatings effectively prevented loss of folic acid during processing at 15, 12, 38, and 7% by wet weight, respectively. The folic acid content decreased significantly in the first 2 months of storage. In conclusion, for the fortification of flour this method was suitable and the SD microencapsulating technique can protect against folic acid loss during processing.

The utilization of banana peels (Musa acuminata Cavendish subgroup) as an alternative ingredient for producing dried plant-based meat products

The utilization and value-added of agricultural by-products have been highlighted for the novel development of food and non-food products nowadays. This study aimed to produce the dried plant-based meat prototype using banana peels to substitute the textured vegetable protein (TVP) and characterize their properties. Banana peels (state 2 or 3 of maturity) were collected and washed to reduce contamination. The pesticide residues and the characteristics (chemical composition and antioxidant activity) of banana peel were analyzed before use. The meat sample (mixed with ingredients such as TVP, banana peel, sugar, salt, pepper, and other components) was prepared, shaped, and dried in the oven (at 80oC) until the moisture content was lower than 15% and divided for four treatments with different proportions of TVP and peels at the concentrations of 0, 25, 50, and 75 %w/w. The physical and physicochemical properties (color, pH, Aw, texture profile), chemical compositions, biological activity, microbiological test, and sensory evaluation (color, flavor, texture, appearance, and overall liking as well as acceptability) were determined. The results revealed a significantly reduced L * , a * , and b * value (p&lt;0.05) with an increase in banana peels added ratio. The different pH and Aw values were not observed in all treatments (p&gt;0.05). There was no significant difference (p&gt;0.05) was observed in protein content among group treatments compared to the control. The meat sample showed a slightly softer texture when compared to the control (p&lt;0.05). There were no pathogenic microorganisms observed in the meat samples. The overall liking (obtained from 30 panelists) was moderately desirable (5.50 points) from the consumer testing. Moreover, 50% (w/w) of substitution showed the highest score (43.3%), while the control was 33.3% on the acceptability test. According to the results, banana peels could be used as an alternative ingredient for substitute TPV in plant-based meat products. These findings could be helpful for the fundamental data to develop plant-based meat to meet consumer requirements.

Conventionally cooked and UV-A light dehydrated beef jerky: Effects on physicochemical properties

This study compared beef jerky produced by conventional cooking and UV-A light dehydration. The analyses included the isopiestic method, colorimetric analysis, electron microscopy, infrared spectroscopy, and microbial inactivation studies. The primary criterion was a water activity (aw) value of < 0.85 to optimize UV-A dehydration time, taking 4.5 h to achieve this level. UV-A light dehydration resulted in significantly less browning compared to conventional cooking, yielding a duller, less red product (P < 0.05). Electron microscopy showed that UV-A light dehydration maintained a more uniform microstructure, while conventional cooking caused more structural deffects. Microbial inactivation studies demonstrated the antimicrobial effect of UV-A light by reducing accessible water (aw < 0.85). The hygroscopicity of UV-A light dehydrated jerky was similar to conventionally cooked jerky. Overall, UV-A light-dehydrated beef jerky had similar characteristics to conventionally cooked jerky but with notable differences that could appeal to specific consumer preferences.

Aspergillus flavus and aflatoxins control in long-term storage of food ingredients of Puerh tea, peanut and polished rice

Aflatoxins are a group of high toxic mycotoxins in food chain. Recent studies showed that aflatoxins might contaminate post-fermented tea, but the result remains controversial. Here, Aspgergillus flavus growth and aflatoxin production were characterized in Puerh tea, peanut and polished rice at different initial water activity (aw) values for long-term storage. As a result, food initial aw value was the critical factor for A. flavus growth and aflatoxin production, and A. flavus almost not grew on foods at aw value lower than 0.8. A. flavus grew best in peanut, followed by rice, but growth on Puerh tea was limited. A. flavus growth was inhibited significantly by adding tea to Potato Dextrose Agar (PDA). Accordingly, aflatoxins produced dramatically in peanut, followed by rice at the first 90 days storage. However, aflatoxin neither produced in Puerh tea nor on tea modified PDA, indicating tea components inhibited A. flavus growth and aflatoxins synthesis.

УВЕЛИЧЕНИЕ ХРАНИМОСПОСОБНОСТИ ШОКОЛАДНЫХ КОНФЕТ ЗА СЧЕТ СНИЖЕНИЯ АКТИВНОСТИ ВОДЫ В НАЧИНКАХ-ГАНАШАХ

According to research by NielsenIQ, the confectionery group is the most rapidly growing one in the food market of our country. The water activity aw value in confectionery has a significant impact on the shelf life of cased sweets with ganache filling. The objective of the study was to develop a method for increasing the shelf life of chocolate ganache fillings by reducing water activity and optimally selecting hydrophilic recipe components while maintaining high organoleptic properties of cased sweets. The objects of the study were: control ganache without adding additional sugars; model samples of ganaches with hydrophilic agents, which included invert syrup, dextrose and sorbitol, taken in the ratio 1:1:1.5 (sample 1); 1:1.5:1 (sample 2); 1:1:1 (sample 3) with 12 % fruit puree replaced. During the studies, the water activity of sample 1 was reduced by 28 %, which allowed the candy to be stored for 60 days with a safety factor of 1.3. The sorbitol content in a ratio of 1.5 to dextrose and invert syrup provided the best microbiological stability, while in the control, which had a water activity of 0.97 %, the QMAFAnM indicators were already exceeded on the 20th day of storage. During organoleptic evaluation it was determined that different contents of invert syrup, dextrose and sorbitol formed different textures of ganache: the control sample had a denser consistency, traces of emulsion stratification, while the model samples retained a plastic, homogeneous filling, and sample 3 had the best flavor throughout the entire shelf life (4.45 points on the 60th day of sto¬rage compared to 4.27 and 4.35 points for the 2nd and 3rd samples, respectively). It is shown that the shelf life of ganache-containing candies for 60 days with preservation of organoleptic indicators can be achieved with a ratio of invert syrup, dextrose and sorbitol as 1:1:1.5.

Effects provided by sugar substitutes upon the quality indicators of model systems of sweetened condensed milk in storage

Sweetened condensed milk (SCM) is a product widely used by both consumers and other food production branches. However, it contains a lot of sucrose. This study aimed to examine the effects provided by sugar substitutes-trehalose, isomaltulose, and polydextrose-upon the SCM sensory profile and valuable quality indicators, such as water activity (Aw), viscosity, acidity, crystal size, and Maillard reaction potential (browning index, color change, loss of free AA). The study was performed by making model systems of SCM (MSCM) using the method of reconstitution of powdered ingredients. All the presented carbohydrate compositions in MSCM provided Aw value typical of intermediate-moisture food, which contributes to the long-term shelf life of the product. However, only 2 MSCM showed stability of Aw within a 14-d storage period: a composition of isomaltulose and trehalose (each at 22.55%), and a composition of trehalose (28.19%), sucrose (5.64%), polydextrose (5.64%), and isomaltulose (5.64%). Trehalose and polydextrose in MSCM with monocarbohydrate added fraction demonstrated their high structure-forming ability, expressed in high values of dynamic viscosity (>30 Pa·s). The MSCM containing a predominant amount of trehalose in the carbohydrate compositions (≥50%) showed lower average crystal size (<16 μm) compared with MSCM with di- and tetra-carbohydrate added fractions with predominant amounts of isomaltulose or polydextrose. Isomaltulose and polydextrose added to MSCM led to pronounced browning, whereas trehalose and sucrose reduced this effect in MSCM with di- and tetra-carbohydrate added fractions. Polydextrose added at 22.55% to carbohydrate fraction of MSCM caused bitterness, whereas the addition at 5.64% did not affect the taste. Based on the results of all the research conducted, the optimal carbohydrate compositions to produce SCM with fewer calories, lower sucrose content, and stable, adequate values of processing and sensory properties were trehalose (22.55%) with isomaltulose (22.55%), and trehalose (28.19%) with sucrose (5.64%), polydextrose (5.64%), and isomaltulose (5.64%).

Impact of silver nanoparticles active packaging on the behavior of Listeria monocytogenes and other microbial groups during ripening and storage of Canastra cheeses

This study aimed to assess the behavior of endogenous microbiota (total mesophilic and psychrotrophic bacteria) during the ripening period and of L. monocytogenes and lactic acid bacteria (LAB) during storage at 5, 10, and 20 °C of artisanal Canastra cheeses packed in a silver nanoparticles packaging system using a predictive modeling approach. The tested packaging system did not influence the initial values of pH (around 5.0) or aw (around 0.95) over the storage. Based on the mathematical parameters obtained by the Weibull predictive model, the active packaging system tested did not inactivate L. monocytogenes during the storage period of artisanal Canastra cheeses. Nonetheless, the findings indicate that the polyethylene packaging system containing silver nanoparticles (3000 ppm active based on silicon dioxide and silver) did not affect endogenous bacteria of Canastra cheese during ripening and storage, which opens the opportunity for the use of this material without compromising the role of these bacteria during cheese ripening, contributing to characteristics of the product's identity.

Identification of water transitions using a combination of moisture sorption characteristics and dielectric properties of different parts of jasmine rice (Oryza sativa).

In this work, water transition points (first transition: monolayer-multilayer water; and second transition: multilayer-free and solvent water) of different parts of jasmine rice including white rice, brown rice and bran were identified through the integration of sorption isotherm and dielectric properties data. Desorption isotherm data were fitted to four established models to select the optimal model for describing the sorption behaviors. Then, dielectric properties such as dielectric constant (ε') and dielectric loss factor (ε″) were measured across various moisture content levels within the frequency range of 200-20 000 MHz. A type III isotherm was observed for all samples and the Peleg model was the best fit with the experimental data. Monolayer moisture content of the samples, estimated using the GAB model, ranged from 3.25% to 4.17% dry basis. For dielectric properties, frequency and moisture dependencies were evident for all sample types. Moreover, the sorption isotherm models effectively described the relationship between water activity (aw) and dielectric properties as reflected by their goodness of fit, and their strong correlation through principal component analysis and Pearson's correlation results. The first water transition occurs at aw values of 0.11, 0.12, and 0.22, while the second transition appears at aw values of 0.9, 0.9 and 0.75-0.85 for white rice, brown rice and bran, respectively. This knowledge will be useful for food processors, providing insights into the optimization of food processing and storage conditions to extend food products' shelf life. © 2024 Society of Chemical Industry.

Use of locust bean flour as a substitute for cocoa in the production of chocolate spread: Quality attributes and storage stability

The effects of locust bean (carob) flour (LBF) as a substitute for cocoa in the production, quality attributes, and storage stability of chocolate spreads were investigated. CON (4.5% cocoa), CF15 (3.0% cocoa + 1.5% LBF), CF30 (1.5% cocoa + 3.0% LBF), and CF45 (4.5% LBF) formulations were produced, and stored at 22 and 35 °C for 12 weeks. Appearance, odor, sweetness, color, and overall acceptability scores decreased with increasing LBF, but up to 3.0% LBF did not affect the scores compared to the CON. Replacing cocoa with LBF at a low level resulted in higher hardness and spreadability. Hardness, free fatty acid, and peroxide values (PV) increased, aw values generally decreased during storage, but PV was still lower than 10 meq O2/kg. As the LBF ratio increased, darkening occurred in the chocolates. Thus, up to 3% of LBF can be used as a cocoa substitute with minimal quality and sensory changes in the production of chocolate spread.

Yacon powder mix: Effects of the composition and the process of microencapsulation by spray drying

Yacon is a tuber known as a healthy food due to its effects as an antidiabetic, anti-inflammatory, anticancer, and prebiotic agent; it is rich in fructooligosaccharides (FOS) and antioxidants, and due to its sweet taste and low-calorie content, it is used as a substitute for ordinary sugar. This research aimed to evaluate the influence of the composition of the feed and the microencapsulation process by spray drying (SD) on the properties of a yacon powder mixture (YP). Response surface methodology with a central composite design with a face-centered composition (α = 1) was used, considering the independent variables: inulin (IN) (3–5% w/w), maltodextrin (MD) (3–5% w/w), air inlet temperature (AIT) (140–160 °C), air outlet temperature (AOT) (75–85 °C) and atomizer disc speed (ADS) (18000–22000 rpm), and the dependent variables: moisture (Xw), water activity (aw), hygroscopicity (Hy), solubility (S), particle size (percentile D10, D50, and D90), total phenols (TP), antioxidant capacity (ABTS and DPPH), color (CIE-Lab*) and yield (Yi). The suspension formulation contained xanthan gum (0.167 %) and a mixture of ascorbic and citric acids (0.3 %). The aw and Xw values of the YP guarantee its microbiological stability; however, the process formulation produces a complex matrix (FOS- sugars- MD - IN) with high affinity for water, which favors adsorption phenomena (hygroscopic material) and high reconstitution (high solubility). The independent variables that best fit the experimental optimization criteria were: IN = 3.0 %, MD = 5.0 %, AIT = 143.7 °C, AOT = 80.1 °C, ADS = 22000 rpm, where Yi = 84.2 %, and the quality of the YP: Xw = 2.4 %, aw = 0.220, Hy = 23.0 %, S = 96.9 %, D10 = 10.6 μm, D50 = 23.4 μm and D90 = 169.3 μm, TP = 1228.2 mg gallic acid equivalent/100 g, ABTS = 2295.9 mg Trolox equivalent (TE)/100 g, DPPH = 5192.3 mg TE/100 g, L* = 80.5, a* = 5.1 and b* = 17.4. SD is an effective technology that positively impacts the development of new food products. In addition, the YP could have multipurpose applications for the industry, generating value in this agri-chain.

Effect of packaging materials and storage duration on the functional quality of red hot peppers (Capsicum annum L.) pods

The preservation of the functional quality of red pepper requires appropriate packaging materials, storage duration, and condition. This study evaluated the effect of the packaging materials and the storage duration on the functional quality of the red hot pepper pod for ten months at ambient storage temperature (25±2 °C) in four packaging materials: Jute sacks, Fertilizer Liner Sheet (FLS), Fertilizer Woven Polypropylene + Liner Sheet (FWPP + LS), and PICS bags (Purdue Improved Crop Storage) using two-factor factorial designs. The samples were analyzed at two-month intervals for water activity (aw, extractable color, total phenolic compounds, pungency index and oleoresin content. Except for aw, other functional qualities of red hot pepper degrade with advanced storage in all packaging materials. At the end of storage, the maximum values of aw (0.76) and the minimum values of aw (0.38) were recorded in jute sacks and PICS bags. Extractable color (ASTA units) decreased from 225.42 to 133.11, 228.71–139.09, 274.29–171, and 288.91–218.98 in jute bags, FLS, FWPP + LS, and PICS bags, respectively. Phenolic compounds (GAE mg/g dry samples) degraded from 2.32 to 1.02, 2.33–1.37, 2.4–1.35, and 2.59–1.85 in jute bags, FLS, FWPP + LS and PICS bags, respectively. The pungency index (Abs/g dry samples) of the samples changed from 4.55 to 2.56, 5.49–4.00, 5.00–3.49, and 4.74–2.72 in jute bags, FLS, FWPP + LS, and PICS bags, respectively. The oleoresin content (%) decreased from 12.88 to 7.18, 12.92–7.78, 13.19–8.45 and 13.58–9.88 in jute sacks, FLS, FWPP + LS and PICS bags, respectively. The study revealed that the PICS bags retained the highest functional qualities compared to other packaging materials.

Cured or fresh? Between fish maturation trends in restaurants and food safety: The case of dry-aged rainbow trout

The application of dry aging on fish is increasing in restaurants worldwide. This process determines fluid loss, changes in muscle texture, and the development of a more concentrated flavour appreciated by consumers. Despite the growing popularity in the foodservice industry, there is a lack of data on potential risks and quality conditions of dry-aged fish. This study was aimed at assessing the safety for consumption of whole rainbow trout subjected to dry aging in a local restaurant (Turin, Italy). Quantitative microbiological analyses and detection of foodborne pathogens were performed on dorsal, ventral muscles, and skin samples at day 0, 3, 6, 10, and 14 of dry aging. Changes in water activity (aw), pH, colour, and biogenic amines in muscle were checked at each sampling point. Almost all the microbiological indicators were below the quantification limits in muscle until day 6 of dry aging, while higher but still acceptable loads were observed at day 10. At day 14, yeasts and moulds exceeded the acceptable level in one case (3.3 ± 0.4 log10 CFU/g) in ventral muscle and counts of Pseudomonas spp. (from 6.1 ± 0.8 to 6.4 ± 0.5 log10 CFU/g), total mesophilic (from 4.4 ± 0.3 to 5.3 ± 0.7 log10 CFU/g), and psychrophilic (from 5.4 ± 0.1 to 5.8 ± 0.3 log10 CFU/g) bacteria indicated the approaching of spoilage. Detection of Listeria monocytogenes and Staphylococcus aureus was always negative during the trials. Minimal changes of pH and colour were observed, while aw values followed a decreasing trend during dry aging. Putrescine was the only detectable amine, with a maximum concentration of 2.05 ± 0.02 mg/kg at day 14. In this study, dry-aged rainbow trout was safe for consumption and 10 days was the most appropriate curing time with 3 °C and 78% of relative humidity. Further studies at different environmental conditions and on other fish species are needed for a comprehensive risk assessment of this fast-growing practice in the restaurant sector.

Impact of sugar reduction on the glass transition temperature and sorption isotherm of freeze-dried tomato powder

The objective of this work was to improve the drying of tomato juices after identifying the main parameters that are responsible for sticking during drying. Glass transition temperature (Tg) which is one of the key parameter, depends on the juice composition, mainly sugar. In order to reduce sugar, centrifugation was applied to the juices. Tg was determined by differential scanning calorimetry (DSC) for freeze-dried tomato juice and tomato pellet conditioned at various water activity (aw) (0.1–0.5). The glass transition curve showed that Tg decreased with increasing of the moisture. Comparison of powders obtained by juice and pellet from centrifugation shows that the Tg of freeze-dried pellets is higher than that of juice at equal aw values. Adsorption isotherms of freeze-dried tomato juice and pellet were determined at 25 °C and a relative humidity (RH) of 0–98% using a dynamic technique. The data obtained were fitted to GAB model that best fitted the experimental data. The equilibrium moisture content (X) value of the freeze-dried pellets are lower and had the same value of 8% dry mass. X is lower because the pellet powders are less hygroscopic than tomato juice powders because of the reduction of soluble compounds by centrifugation, notably sugars. Reducing the product sugar content by centrifugation enables to raise Tg without using carriers and obtain less hygroscopic powders, which is advantageous for product storage.