Blending of nectars and fruit drinks

Several different concentrates can be premixed pri or to the blending step or they can be added to the blending tank (in the case of batch blending). When oil fractions are added at site, they should be thor ough ly mixed into the concentrate prior to the blend ing step. Alternatively, they can be prepared as a water-oil emulsion added at the blending step. Moreover, pulp and wa ter-sol u ble fl a vours may be add ed at the blend ing step.

As the name im plies, NFC is not di lut ed with wa ter, al though NFC having dif fer ent char ac - ter is tics are of ten blend ed be fore pas teur i sa tion. Es sence aroma may also be add ed to NFC at this stage if le gal ly permitted.

If the end product is a nectar or fruit drink, other ingredients are added at the blend ing step. When sugar is added to or ange juice it may no longer be called juice but be comes a fruit nec tar. Regulations stipulate what may be added to fruit nectars. For ex am ple, EU Council Di rec tive 2001/ 112/EC defi nes fruit nectars as fruit juice to which water and sugar have been added. The fruit juice can be as juice, concentrate or powder, and sugar may be substituted by honey or sweetener.

Minimum juice con tents are spec i fi ed for each type of fruit, which for or ange nectar in Europe is 50 %.

Water feed

Vacuum

7.4 Blending

Fruit juice regulations do not cover fruit drinks, which fall under gen er al food leg is la tion. In addi- tion to what may be used for nectars, in gre di ents for still fruit drinks include:

• artifi cial fl avours

• natural and artifi cial colour • stabilisers and antioxidants • preservatives

Stabilisers used to maintain prod uct consistency are, for example, pectin and guar gum, and some pre serv a tives used are ben zo ic acid, sorbic acid and sulphur dioxide. Ex am ples of anti oxi dants are ascorbic acid and sulphur oxide. For orange drinks with low juice con tent, acid needs to be added. Brix level and Brix:acid ratio are typically higher for nectars and drinks com pared with pure juice. Pre serv a tives are not re quired when the product is pas teur ised and asep ti cal ly packed.

Several of the ingredients for drinks (and nectars) are added in very small quan ti ties. They may be added directly to the blending tanks or pref er a bly a premix of these in gre di ents is pre- pared separately. Dissolving granulated sug ar to give a sugar so lu tion of de fi ned con cen tra tion is often done at the juice pack ing plant. Sugar may be dis solved batchwise or con tin u ous ly. Al ter - na tive ly, sugar may arrive as a liquid solution by tank car and pumped to stor age tanks on site. The choice de pends on the amount of sug ar used and the prox im i ty to sugar sup pli ers.

7.4.2 DEFINING THE BLENDING FORMULA The Brix value of the reconstituted juice is the key pa ram e ter for the blending operation. Ap- pro pri ate reg u la tions stipulate minimum con cen - tra tions of sol u ble solids for re con sti tut ed juice. The EU de mands a min i mum value of 11.2 °Brix for orange juice made from con cen trate, whereas the USA sets a minimum value of 11.8 °Brix. The Brix value is meas ured by a re frac tom e ter

and cor rect ed for temperature, and also for acid con tent for concentrates. The Brix value can also be measured with a density meter.

The required hourly output from the blend ing sec tion is determined by the downstream fi ll ing rate and the to tal volume of juice to be pack- aged. The quan ti ties of con cen trate and wa ter to be blended can be cal cu lat ed ap prox i mate ly from the Brix value of the con cen trate and that of the fi nal product. A cal cu la tion ex am ple is shown in the fact box.

Certain tables with density values for pure sugar solutions at different concentrations are used in the citrus industry as a common ref er ence to determine the weight of solids in juice and concentrate. (An ab stract is given in Section 13, Abbreviations weights and measures.)

In practice, the density values are ap prox i mate for or ange juice because it is not a pure sug ar so lu tion but contains varying amounts of in- sol u ble solids and acid. The actual Brix value of con cen trate may differ from the spec i fi ca tion by, say, ±0.5 °Brix. Hence, in the case of or ange juice, the ex act Brix val ue of the fi nal juice can not be cal cu lat ed from a formula, but for high ac cu ra cy it must be de ter mined by laboratory or in-line measurements.

QUANTITY OF CONCENTRATE NEEDED TO MAKE 1 LITRE JUICE

Basis:

Final juice: 11.2 °Brix

Concentrate: 65 °Brix, corrected Calculation:

Juice of 11.2 °Brix has a specifi c gravity of ap- prox. 1.045 kg/l. In other words, 1 litre juice at 20 °C weighs about 1045 grams.

1 litre fi nal juice of 11.2 °Brix contains 1045 x 11.2/100 = 117 grams soluble solids. 1 kg concentrate of 65 °Brix contains 1000 x

65/100 = 650 grams soluble solids. Result:

To prepare 1 litre of juice you therefore need Concentrate: 117/650 x 1000 = 180 g Water: 1045–180 = 865 g

These values are approximate because juice is not a pure sugar solution.

EXAMPLE OF SAVINGS IN RAW MATERIAL