Please login first

List of accepted submissions

 
 
Show results per page
Find papers
 
  • Open access
  • 0 Reads
Thermal properties of expanded amaranth seed oil

Amaranth was present both in the culture and in the cuisine of the peoples of South America already in pre-Columbian times. This pseudocereal is valued for its high content of vitamins, calcium, iron and squalene. The seeds are also used to produce oil and as a snack in the form of expanded amaranth. Thermal properties of oils are a very important distinguishing feature of their quality and stability. Based on the knowledge of the oxidation time, studied with a differential scanning calorimetry, it is possible to determine the susceptibility of the tested oil to oxidation.

The aim of the study was to analyse the properties of fat extracted from extruded amaranth seeds by thermal and chromatographic methods.

The analyses of melting characteristic was performed using a TA DSC Q200 differential scanning calorimeter. All measurements were conducted under a nitrogen atmosphere. Before the test, the sample was stored in refrigerated conditions. The oil was weighed in the amount of 3-4 mg and sealed in hermetic aluminium vessels. The samples were cooled to -80°C and then heated to 80°C at a rate of 5°C/min for melting profile analysis.

Three peaks present on the DSC melting curves of amaranth oil, were connected with the presence of low-melting triacyloglicerols with polyunsaturated fatty acids (first peak) and medium-melting fraction rich in triacyloglicerols with monounsaturated and saturated fatty acids (second and third peaks). Oxidation time analysis was performed using a TA PDSC Q20 pressure differential scanning calorimeter. The oil was weighed in the amount of 3-4 mg into an open aluminium vessel. The samples were then heated from room temperature to 120°C, 130°C and 140°C. All measurements were made under an oxygen atmosphere. PDSC analysis showed good resistance of the oil to oxidation.

The composition of fatty acids in the studied amaranth oil showed a high content of essential fatty acids.

  • Open access
  • 0 Reads
Optimization of enzymatic extraction of melanoidins from bread by-products. Bioactivity and microbiota modulation.

The bakery industry generates a substantial food waste, leading to global environment pollution and economic losses. However, these by-products contain valuable bioactive compounds, such as melanoidins, which are brown pigmented compounds with significant antioxidant, antimicrobial and anti-inflammatory properties, making them ideal functional ingredient. This study aimed to evaluate the optimal enzymatic extraction of melanoidins from bread crust using different proteolytic enzymes: pronase E, serine-endo-protease (SP), metalloenzyme protease (MP) and endoprotease papain enzyme (EP). While the yield of melanoidins from SP and EP was lower than that of Pronase E, it was significant. No cytotoxicity of bioaccessible fractions, gastrointestinal and colonic fraction, were observed in the cell lines Caco-2, HUVEC and SHSY5Y. The antioxidant properties, chelating capacity and ability to stabilize hydroxyl radical were characterized in bioaccesible fractions of the four melanoidins extracts. Moreover, melanoidins showed positively influenced on the intestinal microbiota by increasing beneficial bacteria like Bifidobacterium and Lactobacillus, while reducing non-beneficial bacteria such as Bacteroides spp. and Clostridium leptum, with particularly significant results for SP and EP enzymes extracts. In conclusion, SP and EP enzymes appear to be viable alternatives to Pronase E for obtaining melanoidin extracts as functional ingredients. These enzymes offer potential cost advantages and contribute to the sustainable utilization of bakery by-product melanoidins in various food applications. Implementing these alternatives could help reduce food waste, environmental pollution, and give add value to the bakery industry while promoting the use of valuable bioactive compounds.

  • Open access
  • 0 Reads
Molecular Identification and Phylogenetic Inference of Lactic Acid Bacteria Isolated from Goat’s Raw Milk Cheese

Lactic acid bacteria (LAB) have a wide genetic potential and are applied in areas such as food production, intestinal health, and genetic engineering. Thus, the objectives of this work were: to identify at the species level twenty-eight 16S ribosomal gene sequences of LABs from cheese; and to evaluate the phylogenetic relationship among the sequences. Colony PCR was performed with the primers 15f 5'-GCTCAGGAYGAACGCYGG-3' and 687r 5'-CACCGCTACACATGRADTTC-3'. The identification of the nucleotides was carried out using the Sanger method. The species of the obtained sequences were determined with the BLAST tool. In the R software, a multiple sequence alignment was performed with ClustalW program. Subsequently, an identity matrix containing the squared root of the pairwise distances was calculated, and a phylogenetic tree was built with the Neighbor-Joining method. In the MEGA software, distance between and within species were calculated. LAB sequences were identified as Lacticaseibacillus paracasei (43%), Lactiplantibacillus pentosus (3.6%), Lactiplantibacillus plantarum (10.7%), Lactococcus cremoris (10.7%), Lactococcus lactis (7.1%) and Leuconostoc mesenteroides (25%). The phygenetic tree revealed variability among sequences of the same species from the positions assumed in the cladogram, and allowed the identification of clusters, formed by the species L. mesenteroides, and L. paracasei. The species L. lactis and L. cremoris proved to be the most genetic distant from each other, with 1.6 as the average number of nucleotide substitutions per position. Therefore, L. paracasei has been shown to be the most frequent in the analyzed samples. Further research will yield more understanding of LAB's diverse and phylogenetic characteristics.

  • Open access
  • 0 Reads
Acoustic properties of Chihuahua, manchego, and panela type cheeses, applying ultrasonic spectroscopy

In Mexico, there is a wide variety of cheeses which are produced according to their region of origin. The most common are the type cheeses: aged, white, Cotija, Chihuahua, fresh, mexican manchego, Oaxaca, panela and cottage cheese, to mention a few examples. From which, most are made from cow's milk, and in some cases from goat's or sheep's milk, depending on its type. However, it is very important to determine their qualitative and quantitative properties, as well as nutritional ones through the biological, physical and chemical characterizations that food has, applying various sources of stimulation such as acoustic, electrical, magnetic, mechanical, nuclear, optical, thermal, etc. In this paper, a study to determine the acoustic properties of Chihuahua, manchego and panela cheeses, applying acoustic spectroscopy in the ultrasound spectrum is presented. The products were purchased at a local store in the capital city of Chihuahua. The echoscope block of the GAMPT® acoustic tomograph with acoustic sensors at 2MHz was used to measure the acoustic phase velocity depending on the thickness, with a quasi-regular temperature of 16oC of the environment. The method applied was by transmission with normal incidence. Measurements were performed in triplicate. The volumetric density and acoustic impedance of the cheeses as well as the rheological properties were determined by indirect method. The results show that the acoustic phase velocity of the Chihuahua, Manchego and Panela cheeses were VAFChi ≈ 1221.47m/s, VAFman ≈ 1436.06m/s y VAFpan ≈ 1142.28m/s, respectively. The volumetric density of the Chihuahua, Manchego and panela cheeses were rChi ≈ 1.1577gr/cm3, rman ≈ 1.1138gr/cm3 y rpan ≈ 1.7095gr/cm3 a 12.1oC, respectively. In addition, the acoustic transmittance was explored, where a great attenuation was presented in all the products. It is possible that at a frequency of 2MHz the propagation of the wave through the cheese samples is attenuated as a sum of the absorption and scattering of the wave itself within the cheese structure.

  • Open access
  • 0 Reads
Diversity and Functional Characterization of Lactic Acid Bacteria in Alheira Sausage: Insights for Food Safety and Quality Control

Alheira, a fermented sausage traditionally produced in the Portuguese region of Trás-os-Montes, undergoes a maturation process that reduces pH through the fermentative action of lactic acid bacteria (LAB). In this particular study, the aim was to explore the diversity of LAB in alheira. Twenty-eight alheira samples were collected from various regions of Portugal (including Vimioso, Mirandela, Vinhais, Mogadouro, Povoa de Lila, Bragança, and Valpaços), and LAB were isolated from MRS and M17 agar, and confirmed. After characterization of technological potential, including in-vitro antimicrobial activity against foodborne pathogens and acidification potential, a subset of 63 samples were selected for identification. By conducting genetic analysis of the 16S ribosomal region, the study revealed that Enterococcus faecium (27%) and Leuconostoc mesenteroides (19%) were the most frequently found LAB species. Furthermore, Weissela viridescens, Staphylococcus epidermidis, and Latilactobacillus curvatus were identified in only 1% of the total samples. Interestingly, the regions of Bragança, Valpaços, and Mirandela exhibited the highest diversity of LAB species. When comparing the LAB isolates with the technological features, it was found that Pediococcus, Lactiplantibacillus, and Leuconostoc demonstrated the strongest antagonistic activity against Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus. Notably, Enterococcus, particularly the species E. faecium and E. durans, displayed a higher acidification potential. These findings emphasize the importance of a comprehensive LAB characterization for enhancing food safety and quality control measures associated with alheira production.

  • Open access
  • 0 Reads
Valorizing Grapefruit (Citrus x paradisi Macfad) By-Products: Phenolic Composition and Antioxidant Potential Assessment of Pulp and Waste Extracts

The grapefruit (Citrus x paradisi) is the sixth most consumed citrus fruit worldwide. It's known for its tangy flavor and reddish-pink pulp, primarily consumed as juice or pulp. The peel and mesocarp are discarded, but they contain valuable antioxidant compounds and biologically relevant substances. This study aimed to identify and quantify phenolic compounds in various grapefruit parts and evaluate their antioxidant capacity. Three methodologies (TBARS, DPPH, and OxHLIA assays) were used to assess antioxidant potential. The identification and quantification of the phenolic compounds were performed by HPLC-DAD/ESI-MS. The grapefruit was divided into three parts: peel, mesocarp, and pulp, each of which underwent a hydroethanolic extraction to obtain extracts for phenolic composition identification and antioxidant potential evaluation. The mesocarp was demonstrated to have the highest amount of phenolic compounds (48.4 mg/g of extract), followed by the peel (36.7 mg/g of extract). Moreover, the peel extract exhibited the best result in all three antioxidant activity methods performed. The higher antioxidant activity of the peel compared to the other extract could be attributed to its higher concentration in naringenin and its derivatives, particularly O-triglycosyl naringenin and acetyl naringenin, being these the phenolic compounds found in higher quantities in the peel. Based on the obtained results, both waste and pulp extracts of grapefruit showed to be promising natural ingredients that could be applied in different industrial sectors.

  • Open access
  • 0 Reads
Use of a combined autochthonous starter to ferment Peranzana Alta Daunia table olives
Published: 14 October 2023 by MDPI in The 4th International Electronic Conference on Foods session Food Microbiology

The use of starter cultures for table olives fermentation is highly recommended, since it may reduce spoilage, inhibit the growth of pathogens and help to achieve a controlled process. Despite these benefits, most of the olive varieties are still processed without starter addition. “Peranzana Alta Daunia” is an olive cultivar used to produce an excellent table olive prepared by the Greek style through a spontaneous fermentation in brine without any preliminary treatment. However, spontaneous fermentation is often unpredictable, thus the use of a suitable starter could be an important way to standardize production and provide a correct fermentation course.

The purpose of this study was to evaluate the use of a multiple strain cocktail as starter culture for “Peranzana Alta Daunia” olives; in particular, the effect of the ripening degree (veraison) of drupes (violet or green olives) and of the salt concentration in the brine (6 or 8%) on the acidification kinetic was analysed by using a 2k Factorial Design. A combined starter cocktail including three autochthonous strains (Lactiplantibacillus plantarum, Candida norvegica and Wickeramomyces anomalus) was used.

The acidification was affected by all the variables tested with the verasoin degree as the most significant one; namely, the pH values decreased with the increase of the fruit ripening underlining that the fruit maturity may exert a strong effect on the fermentation course. In fact, neither the brine salt concentration nor the presence of the starter culture were able to improve the acidification kinetic when unripe fruits were used.

  • Open access
  • 0 Reads
Biomass production and use of Saccharomyces cerevisiae var. boulardii in a beverage for athletes
Published: 14 October 2023 by MDPI in The 4th International Electronic Conference on Foods session Food Microbiology

Saccharomyces cerevisiae var. boulardii is the only yeast indicated as a probiotic. In recent decades, sports drinks have become very popular due to their peculiarities of providing health benefits; however, the supplementation of probiotics in beverages or foods requires to address at least two challenges, that is the production of biomass and the viability of probiotics in the product, along with the possible effect on the sensory scores. Therefore, the main topic of this paper, was to study the effects of adding two commercial strains of S. boulardii, labeled as SB1 and SB2, to a beverage intended for athletes by focusing on their viability and consumers’ preference, while as a preliminary step for biomass production the effects of pH, glucose concentration and temperature were studied through the methodology of Central Composite Design. Concerning biomass production, the combination of both response surface methodology and desirability approach highlights the existence of non-linear trends for the effects of temperature and glucose on the growth kinetic, with optimal values depending on the time, that is 30-35°C and 10-15 g/L of glucose after 24 h and 25°C and 15-20 g/L of glucose after 48 h, while pH was less or not significant. Both probiotic yeasts survived in the beverage, although consumers showed a preference for the strain SB2, thus suggesting that the interaction probiotic microorganism/food should be carefully assessed and evaluated in each case.

  • Open access
  • 0 Reads
Improvement of Tenebrio molitor larvae farming and fatty acids composition by supplementation with vegetable waste

Aim: Huge amounts of vegetable wastes are generated by the food industry. Their bioconversion into valuable products (e.g., insect flours) through insect farming is a promising solution to reduce their negative environmental and economic impacts. This study aimed to evaluate the growth of T.molitor larvae and their fatty acids profile after supplementing their diets with different vegetable wastes.

Methods: T.molitor conventional diet (wheat bran) was supplemented (1:1) with tomato or cucumber wastes (from conventional and ecological crops) for 6 weeks. The control group received an equivalent amount of water to compensate for the waste's moisture. Weekly measurements of total larvae weight/tray and individual larval weight and length were taken. Fatty acids were analyzed by GC-MS at the end of the study.

Results: Larvae weight and length progressively increased, particularly between day 15-43 of supplementation. On day 43, the weight of larvae fed with tomato and cucumber showed a 7-fold increase compared to the study’s beginning and almost doubled that reached by control larvae (647-720 vs 370 g/tray, respectively). All supplemented larvae doubled their initial mean lenght, while control larvae were significantly smaller. Supplementation increased polyunsaturated fatty acids percentage by 22-37%, being linoleic acid the most abundant.

Conclusion: This study demonstrates that both tomato and cucumber wastes from conventional or ecological crops are excellent supplements for T. molitor diet, improving their fatty acid composition and reducing in 3-4 weeks the time necessary for larvae growth. This sustainable approach enables the revalorization of vegetable waste, minimizing environmental impact and economic losses.

  • Open access
  • 0 Reads
Sustainable strategies to increase the content of protein, unsaturated fatty acids and vitamins of Tenebrio molitor larvae flours by vegetable waste supplementation

Aim: The food industry generates 2-5% of vegetable wastes. Insect farming offers a solution to convert such wastes into high-added value products like insect flours. Vegetable wastes are rich in bioactive compounds and other essential nutrients, which might improve nutritional composition and quality of insect flours. This study aims to evaluate the effect of supplementing T.molitor diets with vegetable wastes on flour quality.

Methods: Conventional diet (wheat bran) of T. molitor was supplemented (1:1) with tomato (T) or cucumber (Cb) waste for 6 weeks. The control group (C) received water necessary to compensate the waste's humidity. After supplementation, larvae were starved, frozen, blended, dried in a pilot-infrared oven (68ºC for 4 h) and ground to obtain the flours (C, Cb and T). Quality parameters (moisture, colour, lipid oxidation) and nutritional value (vitamins, fatty acids, starch) were determined.

Results: Flour moisture content was similar (3.6-3.8%), although nutritional value and quality attributes of flours differed based on the supplementing diet. The percentage of unsaturated fatty acids increased in Cb and T flours, primarily due to higher levels of linoleic acid (33-37%). Such modification triggered major lipid oxidation and higher luminosity due to fat globules in the flour surface. Vitamins and starch levels were generally similar among flours, enriched in vitamin C (T flour) and B3 (T and Cb flours).

Conclusions: Tomato and cucumber wastes can effectively supplement T. molitor diet and produce flours with higher nutritional value. Besides, this sustainable strategy revalorizes vegetable waste, reducing negative environmental and economic impacts.

Top