Fruit juices Brix, concentration

Tables have been published relating Baume, Brix and specific gravity. As density is temperature dependent it is necessary to either bring the syrup to a fixed temperature or, as is more common in practice, to use temperature correction factors or tables. The relationship between density and concentration is slightly different for invert sugar or glucose syrups. The Brix scale is sometimes applied to products that are not sucrose syrups, such as concentrated fruit juice. Recipes are certainly in use that state boil to x Brix . In practice these instructions mean that the material should give the same reading as a sugar syrup of that concentration. As often happens in confectionery these practices have been proved to work empirically.

Serial dilutions are recommended to ensure accurate measurements of highly concentrated, high density, or dried samples. Perform a weight-by-volume dilution with distilled water to obtain a single-strength solution (e.g., usually around 10° Brix for fruit juices unit hi,4), followed by a second dilution using 0.025 M potassium chloride buffer, pH 1.0. Both dilution factors must be considered when calculating monomeric anthocyanin content. 

Fruit juice Direct juice Rel. density 20/20°C Single-strength minimum Brix (direct juice) From concentrate Rel. density 20/20°C Single-strength minimum Brix... 

The concentration of most fruit juices is conveniently measured in degrees Brix, although the strict interpretation of this measure refers to pure solutions of sucrose in water (e.g. 10°Brix is 10% w/w sucrose in water). For juices with a high proportion of sugars to acids, such as orange, pineapple and apple, this is... 

Brix Passion fruit juice-concentrated Fruit juice-temperature effect 18.8... 

Refractometer readings can be affected by the presence of other dissolved solids. The presence of fruit acids in particular can influence the refractometric Brix reading and should strictly be taken into account when calculating juice concentration. In most cases the effect is not significant however, when there are appreciable levels of acid in the juice, for example, lemon and lime juices, there will be a need to apply the collection. 

The concentrate can go to low-temperature stcrage or directly to processing for FCOJ. During the fruit processing season, cutback juice may be used to dilute the concentrate to 45°Brix. At other times, essence and water are used to prepare FCOJ. Berry and Veldhuis (3) reviewed this process in great detail. 

Apricot was used as a model for studies of fruit puree clarification. Various puree concentrations were treated for 30 min at 50° C with 0.4 cc/L, each, of commercial cellulase and pectinase enzyme and clarified by filtration through a 0.45(im pore size ceramic microfilter. Sparkling clear apricot juice was produced at flux rates from 90-190 L/m2h. Above 13° starting Brix. juice flux showed little increase with increasing starting Brix. Dissolved solids flux increased substantially with increasing starting Brix. Permeate remained clear and retained most of its flavor and aroma when concentrated by vacuum evaporation to 58° Brix. There appears to be some retention of enzymes by the filter. Retained enzymes were successfully utilized in a 4 h trial in which untreated puree was continuously added to retentate. in amounts equal to permeate removed, after startup on enzyme-treated puree. 

Apricot is very representative of the fruits just described. It has a very short harvest season and storage life, and thus the freshmarket is very limited. Because of its short season, a processor will usually convert part of the crop to puree, at 30-32° Brix, for later reprocessing. Consequently, apricot was chosen as a model for our research with the goal of increasing the value of the crop by expanding the market for its concentrated puree. It was felt that this could be accomplished by converting the puree to clarified juice. 

Furthermore, the same authors also showed that at any concentration used in their experiments, the driving force reduction due to the concentration polarisation effect was higher than that of the temperature polarisation effect. For example, at 8 mol/kg, CaCl2 corresponds to 225 Pa of reduction in driving force due to concentration polarisation, whereas the reduction due to temperature polarisation effect is only 75 Pa. The best result obtained by Ravindra Babu et al. (2008) in terms of pineapple juice concentration was up to 62° Brix, preserving the ascorbic acid content of the fruit. 

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