Productive manifestations and technological parameters of juice of selected yellow-green apple hybrids

Абстракт

The purpose of the present study was to evaluate the productivity, fruit quality, and suitability for technological processing of the fruits of apple selections with yellow-green fruit color for the production of cold-pressed cloudy juice. The study was conducted during the period 2018–2021 with 10 apple selections of the Institute of Agriculture - Kyustendil and three hybrids introduced from China through existing agreements on bilateral scientific and technical cooperation on apple cultivar selection and improvement. Juice obtained from each of the assessed apple hybrids and two standard cultivars was produced by cold pressing. The following indicators were determined: juice yield, total sugar content, total acidity, oxidation reduction potential, conductivity, total dissolved solids, salts, and relative weight. Sensory tests of color, aroma, and taste were performed. The ratios between the values of the aforementioned parameters were calculated. We established that hybrids 2/4 and 4/15 were the most suitable for the production of apple juice by the cold pressing method, yielding juice with an excellent taste and organoleptic qualities, color and aroma. Additionally, the highest yield of juice was obtained from these hybrids. Meanwhile, hybrid 4/15 produced exclusive quality juice, which could be defined as premium or luxury. The hybrid 1/14 did not produce juice, by cold pressing but a pulp-like suspension (puree). Therefore, all other studied hybrids can be used for the production of fruit juices by the cold pressing method. Nevertheless, the pre-processing addition of fruits of other, high juice-yielding apple cultivars or fruit species is desirable for achieving better juice quality and quantity.