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Simultaneous optimization of protein, soluble and insoluble dietary fibre, total phenolic content, and antioxidant activity was carried out in apple pomace by using response surface methodology (RSM) and solid state fermentation. A central composite design (CCD) was used to optimize the content of nutritional and functional properties, and two factors were studied: time and temperature of fermentation. The fermentation of apple pomace under the best conditions (29.5 ºC and 4.9 days) allowed the depletion of fermentable sugars, an increase the contents of protein and insoluble dietary fibre (36% and 23%, respectively), while soluble dietary fibre, total phenolic content, and antioxidant activity remained constant. [ABSTRACT FROM AUTHOR]

ABSTRACT The activities of polygalacturonase, pectin lyase, β-glucosidase, β-xylosidase and protease were determined using solid media in 420 wild non- Saccharomyces cider strains identified by internal transcribed spacer-restriction fragment length polymorphism. The identified species corresponded to Hanseniaspora valbyensis, Hanseniaspora uvarum, Hanseniaspora osmophila, Metschnikowia pulcherrima, Candida parapsilosis and Pichia guilliermondii. The most common activity exhibited was that of β-glucosidase (33%), with all the analyzed species having some strains able to develop this activity. Strains of M. pulcherrima showed the greatest capacity to produce β-glucosidase and protease. β-xylosidase was detected in 17 yeast strains belonging to the genera Hanseniaspora, Pichia and Metschnikowia. All of the tested species have some strains with the capacity to develop β-xylosidase activity, except for C. parapsilosis. No strains were able to secrete pectin lyase, while polygalacturonase activity was observed in eight Hanseniaspora strains. Only two strains, belonging to the species H. uvarum and M. pulcherrima, developed three enzymatic activities, namely β-glucosidase, β-xylosidase and protease. PRACTICAL APPLICATIONS The non- Saccharomyces yeasts are very interesting in cider making because of the low level of ethanol in cider. In this paper, it is demonstrated that the yeast isolated from Asturian cider represents a source of several enzymes, which have capacity to release flavor compounds. In this sense non- Saccharomyces strains are being used as inoculated cultures to ferment apple pomace and apple must, with the aim of enhancing the aroma and flavor of the products. [ABSTRACT FROM AUTHOR]

Aims: To analyse the genetic diversity and the dynamics of Saccharomyces strains in spontaneous fermentation in ciders. The effect of the cellar, harvest and cider-making technology were evaluated. Methods and Results: The ecology of spontaneous cider fermentations in the same cellar (Asturias) was studied for two consecutive harvests (2000 and 2001) by using mtDNA restriction analysis. Our results showed that there was a succession of genetically different strains of Saccharomyces during cider production. In general, strains of Saccharomyces bayanus species predominated at the early fermentation steps (begining and/or tumultuous fermentations), while Saccharomyces cerevisiae yeasts were the most abundant at the end of the fermentation. Five S. bayanus strains (patterns III, VII, VIII, XV and XVII) were present at significant frequencies in all the experimental tanks during the two consecutive years. The results of the cluster analysis (unweighted pair group method using average linkage) showed higher similarities for the patterns III, XV, VII and VIII. Therefore, these strains should be considered associated with the microbiota of this cellar. Conclusions: A high polymorphism within populations of Saccharomyces was found throughout the different stages of Asturian production of cider. In all the cider fermentations, a variable number of S. bayanus and S. cerevisiae strains was always present. Our results indicate, over the period of time studied, the existence of the natural microbiota in the cellar. Significance and Impact of the Study: This study has allowed us to gain a better understanding of the role of wild Saccharomyces yeast in Asturian cider fermentations. [ABSTRACT FROM AUTHOR]

The cider-making industry in Asturias generates between 9000 and 12,000 tons of apple pomace per year. This by-product, the remains of the apple pressing, and made up of peel, flesh, seeds and stems, is a valuable material, containing substantial amounts of antioxidant compounds associated with healthy properties. Polyphenols such as dihydrochalcones and quercetin glycosides, and triterpenic acids, among which ursolic acid is a major compound, are the main antioxidant families described in apple pomace. The simultaneous recovery of those families has been accomplished by low frequency ultrasound-assisted extraction. Working extraction conditions were optimised by response surface methodology (RSM): time, 5.1 min; extractant composition, 68% ethanol in water; solid/liquid ratio, 1/75 and ultrasonic wave amplitude, 90%. This procedure was further applied to analyse those components in the whole apple pomace (WAP), apple peel (AP) and apple flesh (AF). On average, dry WAP contained almost 1300 µg/g of flavonols, 1200 µg/g of dihydrochalcones and 4200 µg/g of ursolic acid. These figures increased in the apple peel to, respectively 2500, 1400 and 8500 µg/g dry matter. Two linear multivariate regression models allowed the antioxidant activity of apple by-products to be predicted on the basis of their bioactive composition. The results derived from this study confirm the potential of industrial cider apple pomace as a source of high-value bioactive compounds, and the feasibility of the ultrasound-assisted extraction technique to recover those components in a simple and efficient way.

The objective of this study is the characterization of the phenolic profile and antioxidant activity of elderberries ( Sambucus nigra L.) from a collection of 79 wild specimens in northern Spain to assess variations in the species at the local level and evaluate its interest as a source of biocompounds. Also, a first study was carried out on the microflora present in this fruit, providing information relevant to its commercial exploitation. Moreover, the phenolic composition, antioxidant capacity and microbial composition in overripe fruits were determined, seeking a better use for this currently wasted resource. A wide variability in levels of phenolics was detected. Elderberries showed high antioxidant activity related to a high cyanidin derivative content, making them of interest to industry. Microflorae were present in very variable concentration ranges, so their levels should be monitored in those applications that require strict control. Overripe fruits are of interest as a source of anthocyanidins, since their concentration and antioxidant capacity remain after the optimal ripening period, promoting sustainability and a better use of natural resources. The database generated is of particular interest for further breeding trials based on the phenolic profile and antioxidant activity of the samples.

Nine ciders obtained by cryo-extraction were analysed for chemical, olfactometric and sensory characteristics. Three types of ice apple juices and three autochthonous yeast strains were evaluated. The quantitative volatile profile is mainly influenced by the apple juice. Regarding the olfactometric profiles of the ice ciders, 23 odorants not previously found in Spanish still ciders, and described as sweet, spicy, fruity and floral were observed. Among these, it is worth mentioning 5 high-boiling point compounds found in an olfactometric zone where heavy, phenolic odours predominate in still ciders. The sensory descriptions obtained by Check-All-That-Apply classified the ice ciders mainly by their sweet taste and smoothness, these attributes being the most influential in the assessment of the overall quality of the ciders. The most highly valued ciders were described as the sweetest, most fruity ones, in agreement with their having the highest values for the ratio between total sugars and total acidity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

A total of 350 colonies isolated from a cider cellar in Asturias (Spain) were identified by rDNA ITS-RFLP restriction analysis. Saccharomyces spp. strains were characterized by mitochondrial DNA (mtDNA) restriction analysis. Fifty-four different Saccharomyces spp. strains were identified and tested to ascertain their capacity to carry out secondary fermentation of sparkling ciders. The screening of yeasts to determine their principal enological characteristics (tolerance to ethanol, production of volatile acidity and hydrogen sulphide) was accomplished by means of rapid, non-expensive assays (plate agar). As a result, 13 (24%) of the 54 initial Saccharomyces spp. yeast strains were eliminated. The technological properties assessed were flocculation capacity, ethanol and sulphite tolerance, and production of major volatiles. Ten Saccharomyces cerevisiae strains were characterized as true flocculants; all of these strains were able to grow in ethanolic medium and in the presence of 200mg/l of sulphite. Applying cluster analysis to the production of amyl alcohols, isobutanol, propanol and 2-phenylethanol, the strains were classified in two natural groups. Two flocculent yeast strains referred to as 3' and 50', representative of the each statistical group, were selected together with two reference strains (Saccharomyces bayanus C6 and S. cerevisiae Levuline CHP) to elaborate four sparkling ciders by the Champenoise method. The analysis of variance (p<0.01) among ciders revealed that glycerol, acetaldehyde, ethyl acetate, methanol, propanol, i-butanol and 2-phenylethanol were significantly influenced by the secondary yeast strain. The results of sensory analysis indicated that all the sparkling ciders were scored as good. No significant differences among sparkling ciders were found for odour attributes and taste intensity.