Characteristics of ice juices and ciders made by cryo-extraction with different cider apple varieties and yeast strains.

Two sets of nine ciders were made by cryo-extraction for two consecutive harvests combining three types of ice cider apple juices (mono-varietal, bi-varietal and multi-varietal) and three autochthonous Saccharomyces bayanus yeast strains. The type of juice significantly influenced the pH values and the contents of sorbitol and shikimic acid in the ice juices. The strains used as starters did develop the fermentation producing ciders with alcoholic degrees between 8.75 and 11.52 (% v/v) and volatile acidities lower than 0.55 g acetic acid/L. Regarding the ice ciders, the apple mixture significantly influenced the levels of methanol (higher in mono-varietal ciders), 2-phenylethanol, and some minor acetate esters (higher in the bi-varietal ciders). The last ciders were also more floral, buttery, acidic and bitter than those made from mono- and multi-varietal juices. In the first harvest, the ciders obtained from the bi-varietal apple mixture scored lower for overall sensory quality.

Influence of the method of obtaining freeze-enriched juices and year of harvest on the chemical and sensory characteristics of Asturian ice ciders.

Ice cider is a special product made from apple juices enriched by freezing. In this paper, the method of obtaining the ice juices (cryo-extraction and exhaustion) and the year of harvest have been evaluated. For this purpose, a controlled raw apple mixture and an autochthonous Saccharomyces bayanus strain were used throughout the study. Both the enrichment system and the year of harvest significantly influenced the levels of total phenols, sucrose, malic acid, ethyl acetate and 2-phenylethanol. The ciders made by cryo-extraction presented the higher sugar/acidity and sugar/polyphenol ratios. These ciders were more fruity, less astringent and scored better for quality than those obtained by exhaustion. Additionally, a preliminary assay of juice enrichment by cryo-concentration is described. The corresponding ciders presented higher methanol and lower 2-phenylethanol contents than those obtained by the cryo-extraction and exhaustion methods.