Evaluation of Tunisian Olive Leaf Extracts to Reduce the Bioavailability of Acrylamide in Californian-Style Black Olives.

The aim of this work was analyzing the use of olive leaf extracts (OLE) obtained from two local Tunisian olive tree cultivars 'Chemlali' and 'Sayali' to reduce the acrylamide in Californian-style black olives. The phenol profile, antioxidant, and antibacterial activity of the two OLE extracts were evaluated. The principal phenols found were hydroxytyrosol (1809.6 ± 25.3 mg 100 g-1), oleuropein (2662.2 ± 38 mg 100 g-1) and luteolin-7-O-glucoside (438.4 ± 38 mg 100 g-1) presented higher levels in 'Sayali' variety. Small differences were observed between the two kinds of extracts used; the greatest activity of OLE was observed against S. choleraesuis, with values up to 50% inhibition. The extract of 'Chemlali' cultivar was added to the Californian-style table olive, improving its phenol content and its antioxidant characteristics without negatively affecting its sensorial characteristics; these olives showed the highest firmness and proper quality characteristics. The gastrointestinal activity on the acrylamide concentration showed a partial degradation of this compound through the digestion, although the addition of the extract does not seem influence in its gastrointestinal digestion. These findings prove the usefulness of by-products to generate a high-quality added-value product, and this would also be relevant as a step towards a more sustainable, circular economy model.

Application of Electronic Nose to Discriminate Species of Mold Strains in Synthetic Brines.

The chemical composition of the brine for Spanish-style table olives plays a crucial role during the fermentation process. Traditional laboratory analysis requires a high consumption of reagents, highly qualified personnel, sophisticated equipment, long analysis times, and large amounts of samples. Analysis carried out using an electronic nose (E-nose) offers an alternative, non-destructive technique and is useful in determining alterations in brines caused by microorganisms. In the present research, nine mold strains isolated from spoiled olives were inoculated in synthetic brines to determine the effect of microbial development on sensory quality, volatile profile, and the capacity of E-nose to discriminate altered brines from the healthy ones. The brines inoculated with the mold strains presented negative attributes related to aromas of mold, wood, leather, rancidity and, organic solvents among others. The highest intensity of defect was presented by the brines inoculated with the strains Galactomyces geotricum (G.G.2); three Penicillium expansum (P.E.3, P.E.4, and P.E.20); one Penicillium glabrum (P.G.19); three Aspergillus flavus (A.F.9, A.F.18, and A.F.21); and one Fusarium solani (F.S.11). A total of 19 volatile compounds were identified by gas chromatography. Sensory analysis allowed us to classify the synthetic brines based on the degree of alteration produced by the mold strains used. Also, the E-nose data were able to discriminate the inoculated brines regardless of the intensity of the defect. These results demonstrate the capacity of the E-nose to discriminate alterations in brines produced by molds, thereby making it a useful tool to be applied during the elaboration process to detect early alterations in table olive fermentation.

Effect of High Hydrostatic Pressure in the Storage of Spanish-Style Table Olive Fermented with Olive Leaf Extract and Saccharomyces cerevisiae.

Olives treated according to the Spanish-style are firstly treated with caustic soda and then fermented in brine to reduce phenols. Next, olives are packed and subjected to pasteurization. The effect of different high hydrostatic pressure treatments (400 MPa, 4 and 6 min) was evaluated in Spanish-style table olives fermented with olive leaf extract (OLE) and S. cerevisiae compared with thermal pasteurization (P) at 80 °C for 15 min. HHP and P led to a significant reduction in yeast and aerobic mesophiles after the conservation treatment and during storage (300 days). The physical-chemical properties changed slightly during storage, except for olive hardness; olives treated with HHP presented a higher hardness than pasteurized ones. The CIELAB parameter L* decreased until day 300 in most of the treatments, as well as phenols. The HHP treatment led to significantly higher contents of phenolics (even during storage) than olives submitted to P. Some sensory attributes (colour, aspect, hardness, and overall evaluation) decreased during storage. P treatment caused a decrease in appearance, aroma, hardness, and overall evaluation compared to olives treated with HHP. Thus, the application of HHP in table olives to increase the shelf-life can be considered a valid alternative to P.

Chemical Composition and Functional Properties of Dietary Fibre Concentrates from Winemaking By-Products: Skins, Stems and Lees.

The objective of this study was to evaluate, from a technological and nutritional point of view, the chemical composition and functional properties of the industrial winemaking by-products, namely skins, stems and lees. The chemical and physical characteristics, as well as the functional properties (fat and water retention and swelling capacity, antioxidant capacity, and their prebiotic effect), of the dietary fibre of these by-products were studied. The results showed that the skins, stems, and lees are rich in fibre, with the stem fibre containing the highest amounts of non-extractable polyphenols attached to polysaccharides with high antioxidant activity and prebiotic effect. Lee fibre had the highest water retention capacity and oil retention capacity. The results reveal that winemaking by-products could be used as a source of dietary fibre with functional characteristics for food applications.

Addition of Grape Skin and Stems Extracts in Wines during the Storage to Reduce the Sulfur Dioxide: Impact on Red Wine Quality.

This study aimed to evaluate the usefulness of bioactive extracts obtained from red wine by-products, such as grape skins and stems, for reducing or eliminating the use of SO2 in red wine production. Special attention was focused on guaranteeing the microbiological stability of the red wines and protecting them against oxidation. Therefore, the antioxidant and antimicrobial activities of the extracts and red wines were studied. Red grape stems and skins, by-products of the wine industry, from six types of monovarietal wines, were used. Extracts obtained from stems displayed higher concentrations of total phenolic compounds and higher in vitro antioxidant activity. Both stem and skin extracts demonstrated higher antimicrobial activity against pathogenic bacteria and lower activity against yeasts. In the wines produced, higher antimicrobial and antioxidant activities were observed, mainly in the skin extract batches. This study highlights that bioactive extracts obtained from by-products of wine making could be used to reduce or eliminate the use of SO2 in wine production. In this way, healthier red wines could be obtained while guaranteeing their microbiological stability and protecting them from oxidation. Furthermore, the use of these by-products is strongly associated with the circular economy, as they could help to reduce the environmental impact of the wine industry.

Effects of Different Controlled Temperatures on Spanish-Style Fermentation Processes of Olives.

This work aimed to determine the effect of applying different temperatures during the fermentation process of Spanish-style table olives. 'Manzanilla de Sevilla' (southwest of Spain, Badajoz) and 'Manzanilla Cacereña' (northwest of Spain, Caceres) olives were processed at an industrial scale in table olive fermenters whose brine was subjected to different thermal treatments. One of the three conducted experiments found that maintaining brine at 20-24 °C over a 3-month period led to optimum firmness, better color indices, and greater free acidity and lactic acid bacteria populations in comparison to an unheated control. Furthermore, raising the temperature of the fermenter to 20-24 °C accelerated the fermentation process, provoking better lactic bacteria and yeast growth without affecting olive firmness. The higher fermentation rate (shorter time to completion) associated with temperature-controlled olives also reduced the marketing time of the final product. Controlling brine temperature led to a better aspect and color, higher acidity, lower bitterness, and better overall assessment of processed olives. In addition, 'Manzanilla de Sevilla' olives presented a higher phenolic content than 'Manzanilla Cacereña' olives. Preliminary evidence is presented suggesting that 'Manzanilla Cacereña' olives appear highly amenable to Sevillian-style processing. The present innovative work demonstrates the importance of applying different thermal treatments to brine to control the temperature during the industrial fermentation of table olives during the cold season.

Anti-fungal activity of phenolic sweet orange peel extract for controlling fungi responsible for post-harvest fruit decay.

There is a growing interest in finding safe and natural anti-microbial compounds as a valid alternative to conventional chemical treatments for managing post-harvest fruit diseases. This study investigated the anti-fungal capacity of orange peel polyphenolic extract (OPE) against three relevant post-harvest fungal pathogens, Monilinia fructicola, Botrytis cinerea and Alternaria alternata. OPE extract at 1.5 g/L inhibited (100%) the mycelial growth and conidial germination of the three target fungi. At lower concentration, the effect varied, depending on the dose applied and target fungi. When the anti-fungal activity of the main phenolic compounds in sweet orange peel, namely, the flavonoids (naringin, hesperidin and neohesperidin) and phenolic acids (ferulic and p-coumaric), were evaluated, ferulic acid and p-coumaric acid displayed significantly higher inhibitory capacity in synthetic medium, while the activity of flavonoids was limited. Synergism between compounds was not detected, and the inhibitory activity of OPE may be attributed to an additive effect of phenolic acids. Interestingly, in peach-based medium, ferulic acid remained active against M. fructicola and A. alternata and was more efficient than p-coumaric to control B. cinerea. These results highlight peel orange waste as an excellent source of anti-fungal compounds, suggesting the possibility of using ferulic acid or ferulic acid-rich extracts, either alone or in combination with other post-harvest treatment, as a natural alternative to reduce post-harvest losses and, also, enhance the shelf-life of fruit.

Effect of olive leaf extract combined with Saccharomyces cerevisiae in the fermentation process of table olives.

Yeasts have a great importance in the table olives quality and have been proved more and more as starter cultures. Moreover, the addition of olive leaf extract (OLE) could enhance the nutritional value of table olives, but there are no studies in which added OLE has been combined with yeasts during fermentation. The aim of this work was to determine if the quality and functional value of table olives increases when OLE and a yeast starter are used during a Spanish-style olive fermentation process. Several combinations were used: (1) fermentations trials with OLE combined with a strain of Saccharomyces cerevisiae; (2) fermentations with OLE; (3) control fermentations, with no extract or starter culture. During fermentation performed with the addition of OLE and yeasts, the yeast number remained stable for most of the time, resulting in a slight decrease of yeasts by the end of the process. The phenolic profile of olive flesh and brines of the trials was analysed during the fermentation. The addition of OLE increased the concentration of phenols in olive flesh and brines at the end of the fermentation; in these fermentations, hydroxytyrosol was the most abundant, at around 1700 mg/kg in olive flesh and 3500 mg/L in brines olive flesh, whereas in the control fermentation the concentrations were around 900 mg/kg and 2500 mg/L, respectively. In spite of adding OLE, the fermentation resulted in olives without bitterness. We can conclude that yeast inoculation combined with OLE improves safety, nutritional value and other properties of the final product, without affecting its sensorial qualities.

Estudio del estado nutricional y de la prevalencia de exceso de peso en adolescentes de localidades extremeñas de diferentes tamaños / A study of the nutritional status and prevalence of overweight among adolescents from different size towns in Extremadura

RESUMEN En este trabajo se determina el estado nutricional de adolescentes de Extremadura y la prevalencia de sobrepeso y obesidad en función del tamaño de la localidad de procedencia. Se realizó un estudio con 816 estudiantes de Educación Secundaria Obligatoria y Bachillerato, de ambos sexos, con edades de 13 a 18 años. Los centros educativos pertenecían a municipios de una Región española, Extremadura, de diferentes tamaños (de menos de 5.000 a más de 60.000 habitantes). Se recogieron datos antropométricos y, siguiendo criterios nacionales e internacionales, se determinaron los porcentajes de sobrepeso y obesidad en función del tamaño de las localidades. Los alumnos de localidades rurales (menores de 5.000 habitantes) tienden a presentar valores de diferentes parámetros antropométricos que se relacionan con un menor desarrollo corporal. Aunque hubo variaciones en la prevalecía de sobrepeso y obesidad en función de los criterios utilizados, las localidades de más de 60.000 habitantes presentaron los mayores porcentajes medios de exceso de peso y las rurales, los menores.

ABSTRACT The aim of this study was to determine the nutritional status and estimate the prevalence of overweight and obesity among adolescents from different size towns in the Extremadura Region of Spain. A sample of 816 secondary school students of both sexes between 13 and 18 years of age were evaluated. The educative centers selected belonged to different size towns (populations between <5,000 and >60,000 inhabitants). Different anthropometric measures were taken. The percentage of teenagers with overweight and obesity was calculated following national and international standards and compared by town size. Students from rural towns, <5,000 inhabitants, had the lowest values in some of the anthropometric measures; results that are associated with a lower body development. There were differences in the prevalence of overweight and obesity based on the criteria used, but, in general, adolescents from larger towns (>60,000 inhabitants) showed the highest percentages of overweight, whereas rural populations showed the lowest percentages.

[Nutritional evaluation of adolescent students from Extremadura based on anthropometric measurements]. / Evaluación del estado nutricional de estudiantes adolescentes de Extremadura basado en medidas antropométricas.

INTRODUCTION AND OBJECTIVES: Nutrition is one of the pillars for proper body development and optimal nutritional status. Anthropometric methods are most commonly used for body composition analysis and are an essential part in the assessment of the nutritional status of individuals and population groups. This study aims to assess the nutritional status of adolescents from Extremadura (Spain); to determine variations in body composition according to the percentiles obtained; and to propose these values as a reference to the nutritional status of the adolescent population in Extremadura. MATERIAL AND METHODS: A cross sectional study in the community of Extremadura was performed, including a total of 816 students of Secondary School Education of both sexes; and of all ages in the adolescence stage. The selected secondary schools belonged to populations of different sizes (less than 5,000 to more than 60,000 inhabitants). From the measurements taken, different anthropometric indices were determined and the percentiles 3, 10, 25, 50, 75, 90, 95 and 97 for weight, height and complexion were found. RESULTS AND CONCLUSIONS: There were significant gender differences for height, weight, triceps skinfold, arm muscle area and arm fat area. Boys showed greater figures for height, weight and arm muscle area; however, the triceps skinfold and arm fat area was higher in girls. When compared to other national studies, the average height of our population was lower by about 3 cm in both sexes; the average weight was similar, but our adolescents had a higher proportion of fat in the arm. Extremadura girls seem to have a faster growth, reaching final height at an earlier age than the national average, although this height is below average. The boys had a continuous growth in all ages, maintaining national averages.

Antropometría. Composición corporal. Adolescentes. Percentiles. Estado nutricional.

Evaluación del estado nutricional de estudiantes adolescentes de Extremadura basado en medidas antropométricas / Nutritional evaluation of adolescent students from extremadura based on anthropometric measurements

Antecedentes y objetivos: Una correcta alimentación es uno de los pilares para un adecuado desarrollo corporal y un estado nutricional óptimo. Los métodos antropométricos son los más utilizados para el análisis de la composición corporal y constituyen una parte fundamental en la valoración del estado nutricional de individuos y poblaciones. Este estudio tiene como objetivo valorar el estado nutricional de adolescentes extremeños, determinar las variaciones en la composición corporal de acuerdo a los percentiles obtenidos, y proponer esos valores como referencia del estado nutricional de la población adolescente en Extremadura. Material y Métodos: Se realizó un estudio transversal analítico en la Comunidad Extremeña, incluyendo un total de 816 estudiantes de Educación Secundaria Obligatoria y Bachillerato, de ambos sexos y de todas las edades que comprende la adolescencia. Los centros educativos seleccionados pertenecían a poblaciones de diferentes tamaños (de menos de 5.000 a más de 60.000 habitantes). A partir de las medidas tomadas, se determinaron distintos índices antropométricos y se hallaron los percentiles 3, 10, 25, 50, 75, 90, 95 y 97 del peso, la talla y la complexión. Resultados y conclusiones: Se encontraron diferencias significativas en varios parámetros en función del sexo. Los chicos presentaban una mayor altura, peso y área muscular del brazo; por el contrario, el pliegue tricipital y el área grasa del brazo fue mayor en las chicas. Al comparar con estudios nacionales, la altura media de nuestra población era inferior en unos 3 cm en ambos sexos. El peso fue similar, pero presentaban una mayor proporción de grasa en el brazo. Las chicas extremeñas parecen tener un crecimiento más rápido, alcanzando la altura definitiva a una edad más temprana que la media nacional; sin embargo, la talla final es menor a la media. Los chicos presentaban un crecimiento más continuado en todas las edades, con medias en altura similares a las nacionales (AU)

Introduction and objectives: Nutrition is one of the pillars for proper body development and optimal nutritional status. Anthropometric methods are most commonly used for body composition analysis and are an essential part in the assessment of the nutritional status of individuals and population groups. This study aims to assess the nutritional status of adolescents from Extremadura (Spain); to determine variations in body composition according to the percentiles obtained; and to propose these values as a reference to the nutritional status of the adolescent population in Extremadura. Material and methods: A cross sectional study in the community of Extremadura was performed, including a total of 816 students of Secondary School Education of both sexes; and of all ages in the adolescence stage. The selected secondary schools belonged to populations of different sizes (less than 5,000 to more than 60,000 inhabitants). From the measurements taken, different anthropometric indices were determined and the percentiles 3, 10, 25, 50, 75, 90, 95 and 97 for weight, height and complexion were found. Results and conclusions: There were significant gender differences for height, weight, triceps skinfold, arm muscle area and arm fat area. Boys showed greater figures for height, weight and arm muscle area; however, the triceps skinfold and arm fat area was higher in girls. When compared to other national studies, the average height of our population was lower by about 3 cm in both sexes; the average weight was similar, but our adolescents had a higher proportion of fat in the arm. Extremadura girls seem to have a faster growth, reaching final height at an earlier age than the national average, although this height is below average. The boys had a continuous growth in all ages, maintaining national averages (AU)

A low-cost procedure for production of fresh autochthonous wine yeast.

A low-cost procedure was designed for easy and rapid response-on-demand production of fresh wine yeast for local wine-making. The pilot plant produced fresh yeast culture concentrate with good microbial quality and excellent oenological properties from four selected wine yeasts. The best production yields were obtained using 2% sugar beet molasses and a working culture volume of less than 60% of the fermenter capacity. The yeast yield using 2% sugar grape juice was low and had poor cell viability after freeze storage, although the resulting yeast would be directly available for use in the winery. The performance of these yeasts in commercial wineries was excellent; they dominated must fermentation and improved its kinetics, as well as improving the physicochemical parameters and the organoleptic quality of red and white wines.

Determination of killer activity in yeasts isolated from the elaboration of seasoned green table olives.

In this work 51 yeasts strains isolated from seasoned green table olives and belonging to the Candida, Debaryomyces, Kluyveromyces, Pichia, and Saccharomyces genera were characterized by their killer activity in different conditions. Killer activity of isolates was analyzed in a medium with different pH's (3.5 to 8.5) and NaCl concentrations (5, 8, and 10%). At every pH tested, all the genera studied had killer strains, although the smallest percentages of killer yeasts were found at the highest pH (8.5). The presence of 5 and 8% NaCl increased the detected killer percentage, but the highest salt concentration (10%) decreased it. The interaction between the reference killer yeasts and yeasts isolated from olives was analyzed. Most isolates were killer-sensitive to one or more killer reference strains. Only 2 of the 51 strains tested were considered killer-neutral. Cross-reaction trials between isolates and spoilage yeasts showed that, of the isolates, nine killer strains, belonging to Debaryomyces hansenii, Kluyveromyces marxianus, Pichia anomala, Pichia guilliermondii, and Saccharomyces cerevisiae, had the broadest spectra of action against yeasts that cause spoilage. These killer yeasts and the toxins that they produce are candidates for further investigation as suppressors of indigenous olive table yeast growth. The results confirmed the highly polymorphic expression of the killing activity, with each strain showing different killer activities. This method may thus be very useful for simple and rapid characterization of yeast strains of industrial interest.

Characterisation of microbial deep spoilage in Iberian dry-cured ham.

The purpose of this work was to investigate the micro-organisms involved in overlooked "bone taint" spoilage of dry-cured Iberian hams. The physico-chemical characteristics of spoiled hams with 12 and 24 months of ripening, showing initial signs of alteration, were analyzed and their correlations with microbial counts studied. The spoilage potential of different microbial groups was assessed by the relationship between the microbial counts and the proteolysis level of spoilage as observed in the degradation of myofribrillar and sarcoplasmic protein fractions and in the changes in free amino acids. Non-enteric gram-negative bacteria (NEGN) were the dominant microbial group, showing a positive correlation with the moisture of spoiled hams. The Catalase-positive cocci (GPCP) growth was favoured by high NaCl concentrations in the spoiled hams, whereas the counts of Enterobacteriaceae were negatively affected by high NaCl concentration. The highest proteolytic microorganisms were the Gram-negative microbial groups playing Enterobacteriaceae a major role in the undesirable changes of the texture properties of the spoiled hams. With respect to the sensorial analysis, a synergy between NEGN and GPCP was observed in most of the strongly spoiled samples.

Rapid differentiation of lactic acid bacteria from autochthonous fermentation of Iberian dry-fermented sausages.

The populations of lactic acid bacteria (LAB) in different types of Iberian dry-fermented sausages from central-west Spain were identified. A simple and rapid electrophoretic method of whole-cell protein profiles was evaluated, correlating it with 16S rRNA gene sequence analysis and biochemical identification by API 50 CHL. A total of 96 isolates were identified by SDS-PAGE showing stable profiles corresponding to 30-45 polypeptides in the range 95-8kDa that were clearly different for the different species and were grouped with those of the 9 reference strains used in this study. The SDS-PAGE method showed that the predominant species were Pediococcus acidilactici (48%) followed by Lactobacillus plantarum (23%) and Lactobacillus brevis (18%). The identifications obtained by this approach were confirmed by sequencing the V2-V3 region of the 16S rRNA gene and by a BLAST search of the GenBank database. However, biochemical identifications by API 50 CHL showed different errors at the genus and species level. In sum, the SDS-PAGE analysis showed itself to be a rapid and accurate differentiation method for the most commonly encountered LAB isolates in dry-fermented sausages.

Identification and characterization of yeast isolated from the elaboration of seasoned green table olives.

The purpose of this study was to investigate the yeast population during the processing of green table olives. In the fresh olives, yeast were found at concentrations of around 3.0 log cfu/g, with Cryptococcus spp. being predominant. In the brine, the yeast concentrations were greater than 4.9 log cfu/ml, with Pichia anomala, Kluyveromyces marxianus, and Saccharomyces cerevisiae being the predominant species. Unlike the yeast isolated from the fresh olives, the strains obtained from the olive brine mostly showed low pectolytic but high catalase activities. Some of these strains also exhibited other biochemical desirable properties for the fermentation of green table olives, including their lipolytic activities and their assimilation or production of organic acids in the brine. Seven strains in particular of P. anomala, K. marxianus, S. cerevisiae, and Candida maris showed the best properties for use in trials as starter culture in pilot fermenters.

Identification of fungal contamination and determination of mycotoxigenic molds by micellar electrokinetic capillary chromatography in smoked paprika.

The purpose of this work was to analyze the fungal contamination in smoked and unsmoked paprika processed from different cultivars of pepper and to investigate the ability of these and other mycotoxigenic molds to grow and synthesize mycotoxins in smoked paprika. Eighteen mycotoxins were evaluated using micellar electrokinetic capillary chromatography. No relevant differences were found in fungal contamination between smoked and unsmoked paprika. The number of yeasts obtained was low, ranging from 0.4 to 3.29 log CFU g(-1); most of the yeast strains were identified as Cryptococcus spp. followed by Candida spp. All mold counts were <4 log CFU g(-1). Aspergillus, Cladosporium, Penicillium, and Fusarium were the predominant hyphomycete genera. Six mycotoxins were identified in the extracts of several strains isolated from paprika and incubated on malt extract agar. Penicillium expansum followed by Penicillium citrinum and Penicillium raistrickii were the dominant mycotoxigenic fungi isolated. Most of themycotoxin-producing fungi produced detectable amounts of mycotoxins when grown on paprika agar.