Citrus processing

D. A. Kimball, Citrus Processing Quality Control and Technology, Van Nostrand Reiohold, New York, 1991. 

Reed, J.B., Hendrix, C M. Jr., Hendrix, D.L. 1986. In Quality Control Manual for Citrus Processing Plants. Volume I. INTERCIT, Inc. Safety Harbor, FL. 

The following protocols are primarily conducted to ensure the quality of citrus oils during various phases of citrus processing. Citrus processors must account for quality and quantity of citrus oils sold to flavor houses. This not only includes monitoring recovered oils (i.e., cold-pressed oil, essence oil, and J-limonene) but also the total available oil. 

Basic Protocol 7 was developed to estimate the mass balance of J-limonene within a citrus processing plant. However, the calculations must be normalized to provide a basis of comparison. This is achieved by determining the moisture content of those samples. Samples are dried at low temperatures under a vacuum. This removes the moisture in the sample and prevents any decomposition of the remaining solid matter. 

The reactivity of hydrocarbons in citrus oils has brought considerable attention to citrus processing. Processors are only allowed to emit certain levels of volatile organic compounds... 

Kimball, D.A. 1999. Citrus Processing A Complete Guide, 2nd ed., pp. 191-246. Aspen Publishers, Gaithersburg, Md. 

JA Manthye, K Grohmann. Concentrations of hesperidin and other orange peel flavanoids in citrus processing byproducts. J Agric Food Chem 44 811-814, 1996. 

Data from a statistical report ( ) indicated that over one million tons of dried citrus pulp and pellets were produced during a recent season from the Florida crop, which was about 70% of total U. S. citrus production. This by-product is important to the function of the citrus processing industry and to many livestock producers who use it as a cattle feed supplement. 

Praschan, V. C. "Quality Control Manual For Citrus Processing Plants" Intercit, Inc. Safety Harbor, FL, 1975 pp. 61-62. ... 

Varsel, C. 1980. Citrus processing as related to quality and nutrition. In Citrus Nutrition and Quality (S. Nagy and J.A. Attaway, eds), pp. 225-271. ACS Symposium Series no. 143, American Chemical Society, Washington DC. 

Endogenous pectin esterases play an important role in citrus processing they have therefore been studied intensively. They cause cloud loss in citrus juices, which is due to the calcium precipitation of enzymatically de-esterified pectin. This is desirable in the production of lemon and lime juices but undesirable in the production of orange juice. In orange juice concentrates strong calcium pectate gels may form which cannot be reconstituted... 

D-Limonene is regulated as an air pollutant in Florida when released from citrus processing plants, because it can combine with NO to form ozone, contributing to smog, on hot days. The legislation establishes that 65% of the citrus oil (o-limonene) be captured for all plants. Most plants now capture between 40% and 45% of the oil. 

During industrial citrus processing, a part of the essential oil passes to the juice, depending on the extraction method, and contributes to the aroma. In the juice, essential oils are present in the range of 0.0005-0.004%, and these levels can increase to 0.01-0.1 during extraction due to contamination from the flavedo (Primo, 1997). Modem juice extraction methods tend to minimize oil contamination. 

Mamma, D., Kourtoglou, E., and Christakopoulos, P. (2008). Fungal multienzyme production on industrial by-products of the citrus-processing industry. Bioresour. Technol. 99,... 

Table III. Production of Polysaccharide Degrading Enzymes by Microbial Fermentation of Citrus Processing Wastes3...

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