Juice sacs

In one extractor (FMC Inc.), the fmit is located between two cups having sharp-edged metal tubes at their base. The upper cup descends and the many fingers on each cup mesh to express the juice as the tubes cut holes in the top and bottom of the fmit. On further compression, the rag, seeds, and juice sacs are compressed into the bottom tube between the two plugs of peel. A piston moves up inside the bottom tube forcing the juice through perforations in the tube wall. A simultaneous water spray washes the peel oil expressed during extraction away from the peel as an oil—water emulsion the peel oil is recovered separately from the emulsion. 

Much of the FLS biochemical and structure/fimction analysis has focused on a protein from C. unshiu (mandarin). A cDNA was isolated based on sequence homology to an Arabidopsis FLS EST (153O10T7) and used as a probe to determine regulation of gene expression [92]. Higher expression was observed in young leaf, flower, peel, and juice sac/segment epidermis tissues. Expression decreased with tissue age, as has been observed for citrus CHS, CHI, and F3H [57]. Southern analysis... 

Botanically speaking, citrus is a hesperidium, a berry with a leathery aromatic rind and a fleshy interior divided into sections. As shown by the cross section shown in Fig. 6.1, the exo carp or peel consists of an outer layer called the flavedo which contains oil glands and pigments and a white spongy inner layer called the albedo. The fleshy interior or endocarp of the fruit consists of wedge-shaped sections (segments) filled with multiple fluid-filled sacs or vesicles. These juice sacs constitute the edible portion of a citrus fruit. The cytoplasm contents provide the primary source of the citrus juice. The juice consists primarily of water, sugars, pectins, lipids, terpenes, amino acids, phenolics, carotenoids and minerals. 

Figure 7. Maturity effects on naringin and other flavanone glycosides in juice sacs of Texas Ruby Red grapefruit (A) naringin by Davis value (B) total flavanone glycosides by TLC (C) naringin by TLC (25) and (D) naringin by...

In pink and red grapefruit juices the main pigment is lycopene. Ting and Deszyck (50) found 1.3 mg and 2.3 mg of lycopene in 100 g of pink and red grapefruit, respectively. They also reported the fruit to have 0.5 mg to 1.4 mg (3-carotene per 100 g. Purcell (51, 52) found up to 1.8 mg lycopene and 0.49 mg carotene/100 g in juice sacs in Texas Ruby Red grapefruit. 

Occurrence and Distribution. PE was found associated with structural elements of the orange. McDonnell et al. (17) reported no activity in filtered orange juice, but found 58, 44 and 28 PE units per kg wet tissue in flavedo, albedo and cell sacs respectively. Working with four varieties of Florida oranges and Dancy tangerine, Rouse (20) showed that juice sacs had the highest... 

Isoenzymes. Multiple forms of citrus PE were reported by Evans and McHale (AO) and Versteeg et al. (Al). PE was purified from West Indian limes and Navel oranges by fractionation of the whole fruit extracts with (NH. SO (AO-65%), adsorption and elution from Sephadex G-75 columns (AO). The PE active fractions were combined and concentrated before separation into two active PEs on the basis of their elution volume from a DEAE Sephadex A-50 column. Orange PEI (OPEI) and lime PEI (LPEI) had the same elution volume also OPEII and LPEII had the same elution volume. A higher concentration of NaCl was required at all pH values for optimum activity of OPEI and LPEI than of OPEII and LPEII. When the component parts of oranges were separately analyzed chromatographi-cally with DEAE-Sephadex A-50, OPEI was detected only in the peel, whereas OPEII was identified in juice sacs and section walls (AO). 

Dried Pulp, Peel Oils, Pulp-Wash Solids, Dried Juice Sacs... 

Juice and concentrate quality is controlled by regulations, resulting in manufacture to uniform standards worldwide however, less control is exercised over certain by-products and specialty products. Some of the factors important to quality of the specialty products, dried pulp, peel oils, pulp-wash solids, and dried juice sacs will be included in the following discussion. 

The juice vesicles, or "sacs," remaining after juice extraction and pulp-washing may be included in the portion of peel residue dried as cattle feed. However, it is feasible to recover and utilize this material as either frozen (3) or drum-dried juice sacs (44). 

Dried citrus juice sacs have excellent water and fat absorption capabilities, absorbing 10 to 12 times and 4 to 5 times their weight of water and fat, respectively. These absorptive properties make dried juice sacs valuable as emulsifiers or binders for comminuted meat products like luncheon meats, bologna, sausages, and frankfurters. 

The chemical composition of dried orange juice sacs is as follows (44) crude fiber (18.9%), protein (9.0%), pectin (20.6%), ash (3.1%), fat 2.07.), moisture (10%), and other mostly carbohydrate material (36.4%). Another report (46), compared dried juice sac composition with whole peel and core material and found the three to be similar in composition. 

Occasionally citrus juices will contain a few dark specks. This is generally caused by juice or juice sacs becoming scorched or burned either during pasteurization or evaporation. Dark specks are objectionalbe and any given sample of juice should contain very few. All dark specks should be examined with a wide field microscope to determine that the specks are scorched pulp and not some other kind of material. 

The presence of surface or floating juice sacs may significantly affect sensory evaluation of citrus juices. Amount of floating pulp in any particular retail product is primarily dependent on corporate specifications as per their beliefs. When testing frozen concentrated citrus products containing signifi-... 

Separates, based on particle size, the internal elements of the citrus. Collects juice and juice sacs. 

Upon completion of the extraction cycle the internal portions of the citrus are located in the prefinisher tube. At this time, the orifice tube moves upward, placing pressure on the contents of the prefinisher tube. This causes the juice and the juice sacs, due to their small particle size, to flow through the holes of the prefinisher tube and into the juice manifold. Particles larger than the holes in the prefinisher tube are forced through an opening in the orifice tube and discharged out the bottom. 

Adapted from Braddock and Graumlich (4). Values reported are total of respective fraction in peel, juice sacs, segments and seeds. 

Fruit and variety Year Peel (Flavedo albedo) Membrane, core seeds (Rag) Juice sacs (pulp) Juice... 

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