7. PROCESSING AT
8.3 Components added back to juice
The overall juice quality is already determined at the fruit processor by the choice of raw ma te ri al (quality and variety of oranges) and ex trac tion methods. Further processing cannot in crease juice quality. On the contrary, during some processing steps, e.g. evaporation, the juice loses most of its original freshness and aro ma. To provide the de- sired fl avour char ac ter is tics in reconstituted juice, volatile fl avour and fl oating pulp can be added back at different steps of orange juice processing and packaging (see Figure 8.7).
Fruit processors
At the fruit processor, peel oil is often added to concentrate before frozen bulk storage in tanks. It is believed that the oil-soluble volatile components help to mask any processing off-fl avours present in or ange juice reconstituted from concentrate. A typ i cal concentration of added peel oil in juice concentrate before storage is 0.008 % v/v. This low level still allows addition of a fl avour package to the juice for reconstitution at single-strength concentration at which it is consumed.
Blending houses
Blending houses supply juice packers with con- cen trates of consistent quality. Along with blend- ing concentrates of different origin, fl a vour addi- tion is important to achieving product uniformity. By altering the amounts and types of vol a tile fl a- vours added, blending houses can pro duce or ange
concentrates with different char ac ter is tics. Floating pulp is added to improve the mouth- feel of juices and to give a fresher ap pear ance. The pulp can be added directly to the con cen trate by the blending house.
Juice packers
The juice packer can modify the taste of or ange juice by adding selected volatile fl avours before fi nished product pack ag ing.
Oils are diffi cult to mix homogeneously with single-strength orange juice, and therefore need to be added to the juice concentrate before re con sti tu tion. This is usually achieved with a batch premix system. It is possible to disperse a max i mum of 2 % oil into FCOJ at a minimum 42 °Brix. This should preferably be done under a ni tro gen blanket. The premix can be kept over night under refrigerated conditions ready for pro duc tion the next day. Before reconstitution, the premix blending time into the concentrate should be not less than 30 minutes to assure an even dis tri bu tion of fl avours in the fi nal product.
Add-back: • Peel oil Add-back: • Peel oil • Essence oil • Essence aroma • Floating pulp Add-back: • Flavour systems • Floating pulp
FRUIT PROC ES SORS BLENDING HOUSES JUICE PACKERS
Fig. 8.7 Volatile fl avours and fl oating pulp.
In general, the addition of water-soluble aro mas can be carried out at any time during the re con - sti tu tion process. Normally they are added either together with the oils in the premix or lat er at the reconstitution step. Since the water-soluble aromas contain the most volatile fl avour compo- nents, they should be added as late as pos si ble in the process.
A fl avour system based on terpeneless oils pro vides the juice packer with a tool to simply optimise the juice taste with one single addi- tion of fl avours. Since terpeneless oils are much more water-soluble they can be added to single- strength juice.
In this context it should be noted that the ad di tion of fl avours is not the single answer to good juice taste. A sophisticated and well-bal- anced fl avour system can enhance the fl avour of a juice but can never fully mask the off-fl avours from a badly produced concentrate.
When pulp is added back to the juice at the juice packer, it has fi rst to be crushed or thawed be- fore being added back to the blending tank. Pulp packed in 20 kg boxes can be left at am bi ent tem per a ture for a few days to thaw, or the blocks of pulp can be sliced into smaller piec es and thawed in water. Nevertheless, both meth ods are very labour-intensive.
If pulp in 200 l drums is used, crushers sim- i lar to the ones used to thaw frozen NFC are needed since the time need ed to thaw a drum is long enough to result in microbial problems. The labour-in ten sive part of pulp thawing can be
avoid ed by us ing aseptic pulp. However, there are only a small number of aseptic pulp suppliers on the market.
The pulp is added to the concentrate in the reconstitution tank before it is diluted. Constant low-speed agitation of the tank is necessary to obtain even distribution of cells. Moreover, it is very important to prevent too much air from en ter ing the juice during tank agitatation (see sub sec tion 4.2).
• The quality parameters that need protection during storage and what affects them.
• The role of oxygen in vitamin C degradation, juice browning and fl avour changes.
• The impact of light on juice quality.
• Orange juice aroma and the effect of different package types on aroma retention.
• Different types of packaging systems.