Manufacturing of grape fruit juice

The grapes are washed in acid or alkaline solutions, then in water to remove spray residues. Grapes are then conveyed to a stemmer/ crusher, which then remove residual stems, leaves and petioles form the fruit.

Once the stemmed/crushed grapes are separated from the vines, the grapes are heated to about 180 °F (82.2 °C) to extract pigment from the skins, after which the heated material is subjected to mechanical pressure while enclosed in cotton press cloths. Hot pressing is appropriate for deeply pigmented grapes where maximum color extraction is desired.

Whereas, the immediate or cold press procedure is necessary to maintain the initial color of light colored grapes.

The juice is then filtered pasteurized by heating to 170 °F (76.7 °C) and stored in bulk in covered tanks at about 40 °F (4.4 °C). This provides for the separation of tartaric acid salts.

Tartrates must be precipitated. Otherwise, it will settle out upon cooling or even when filtered juice is refrigerated.

This juice is then siphoned off from the tartrate and treated with enzymes, which break down pectins, or with casein for purposes of clarification. Typically, 50-100 ppm of pectinase enzymes is sufficient for the de-pectinization prices at this stage.

The juice is then filtered and bottled. The bottles are capped and then pasteurized by heating in water at 170 °F (76.7 °C) for 30 min.
Manufacturing of grape fruit juice

Concord grapes

The Concord grapes is a robust grape cultivated from ancestral native species or a derivatives of a wild Vitis labrusca grape that could withstand the harsh New England weather. Concord grapes were first developed near Concord, Massachusetts by Ephraim Wales Bull in 1849.

It grew from a seed planted in 1843, which bore fruit in 1849. Prior to the appearance of the Concord, grape growing in Eastern American had limited success.

The only sugars are found in Concord grapes are glucose, fructose and sucrose, and the major nonvolatile acids found were tartaric and malic.

The Concord grape variety is chiefly used for the manufacture of grape juice. Approximately 96% of the juice made in New York state is prepared from Concord Grapes. Natural acidity, color and aroma of fresh grape berries provide quality in single strength Concord grape juice. Acidity above 0.85% results in juice that is too tart.

Hot pressing of the grapes is important to extract anthocyanin pigments, flavor components, amino acids, organic acids, sugars, minerals, tannins, and other ingredients.
Concord grapes