Citrus waste

The main carbon source for production of SCP is petroleum. It has been practised in many companies around the world. Other potential substrates for SCP include bagasse, citrus wastes, sulphite waste liquor from pulp and paper, molasses, animal manure, whey, starch, sewage and agricultural wastes. 

In beverages, carrot pomace, or citrus waste will stabilize the natural color, improve the vitamin and fiber content, enhance the viscosity (mouthfeel) (Laufenberg et al., 1996), and enrich or adjust the cloudy appearance (Sreenath et al., 1995). The organoleptic and chemical properties offer a widespread use in healthy and functional drinks and selected fruit juices. 

Widmer, W. and Montanari, A. M. (1995). Citrus waste streams as a source of phytochemicals. In "107th Annual Meeting of the Florida State Horticultural Society, Orlando/ Florida, USA", pp. 284-288, Vol. 107. 

Exactly when making of jelly first became a household art is not known. As early as 1750, instructions were published for the preparation of apple, currant, and quince jellies. As the art developed, concentrates were made from pectin-nch. sources, starting in the early 1900 s with the use of apple pomace in Germany and of citrus wastes in Italy. The industry soon spread to the United States, with the production of pectin concentrates from apple pomace for use in industrial and household production of jellies. By the middle 1920 s, the citrus producers had entered the field, competing with the dry pectins now available from apple pomace. Competition, and multiple sources of raw material, led to the production of pectins with various jelling properties. Increased knowledge, plentiful raw material, and substantial financial support from the citrus industry eventuated in the currently available modifications of the natural product, low ester pectins ( low methoxyl ), pectates, and pectinates. 

Bioconversion of high value products such as vitamins, organic, and amino acids has been most successfully exploited by the pharmaceutical industry. The use of citrus wastes as a substrate for fermentation of these types of products has recently received attention. Successful application depends on removal of nonspecific inhibitory agents from the peel, press residue, and distillation residue by ion exchange or by physical separation. 

Pectin. Commercial extraction of pectin from citrus involves treatment of citrus waste at pH extremes with concentrated acids. 

In addition to the harsh extraction conditions, not all citrus waste is amenable to conventional pectin extraction. Mandarin orange peel becomes jelly-like on heating and separation of pectin from the residue is difficult (27). Milder extraction conditions and more effective extraction has been reported if mandarin citrus peel was suspended in water with Trichosporon pencillatum for 15 to... 

Protein enrichment Aromas Neurospora sitophila Sugar beet pulp or citrus waste [47]... 

Dietary Fiber from Citrus Wastes Characterization... 

Table II. Proximate composition of citrus waste material.

The use of a 0.05 M NaOH to extract the AIS of citrus tissues removes all the pectins (7). In all three types of citrus waste components these hydrolysates contained mostly uronlc acids, but arabinose, galactose and small amounts of xylose were also present (Table IV). Arabinose is generally 2 to 3 times higher than galactose. In some samples, especially in the peel of Pineapple orange, considerable amounts of rhamnose were found. Only a small amount of rhamnose was found in the Valencia peel seunple and none in the grapefruit... 

Table III. Percent distribution in fractionation of AIS of citrus waste components...

Bamboo Citrus waste Food waste Switch grass Com oil... 

Many of the chemical properties and economic uses of pectins have been reviewed (Aspinall, 1970,1980 Fishman and Jen, 1986). Most commercial pectins come from apple pomace, citrus waste, and sugar beet pulp. 

Tate and Lyle claims for the economics of their Belize plant are that they will produce a SCP from citrus wastes for between 160 to 200 per ton, competing with imported soybean meal at an average price of 270. 

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