Citrus products

Miscellaneous Determinations. Several other problems are deserving of brief mention. The citrus industry, for example, would welcome an improved and more rapid method for determining volatile oil in citrus products. The tomato canning industry could profit by more rapid and accurate methods for determining tomato solids, and also by a method that would predict the increase in viscosity which takes place during concentration. 

Methenamine, methenamine salts Avoid excessive intake of citrus products, milk, and milk products. 

APCI can help to reduce matrix effects when analyzing for carbamate insecticides. Eor example, when analyzing for methiocarb in citrus products, the apparent recoveries were in the region of 50% with ESI. However, on changing to APCI, the apparent recoveries were increased to 110%. This is an example where APCI can be an alternative API method if matrix effects are a problem with ESI. It is important to note that the analyte must show sufficient sensitivity to both API techniques. 

Girard, B. and Mazza, G. 1998. Functional grape and citrus products. In Functional Foods Biochemical and Processing Aspects (G. Mazza, ed.), pp. 139-191. Technomic Publishing, Lancaster, PA. 

Pest Control in Citrus Production in Tropical and Subtropical America... 

This discussion covers the field only briefly. Numerous diseases and insects have been omitted which are tied more to certain areas. That the problems are important is attested by the fact that citrus production is the largest world-wide fruit-producing industry, while in the United States it exceeds the total of apples, pears, and peaches combined. As citrus is grown so extensively in so many areas where organized research is lacking, technical information is of paramount importance. 

As far as permanent crops are concerned. La Mantia and Barbara (1995) compared the energy consumption on one organic and one conventional olive and citrus farm in Sicily, Italy. They found a lower energy consumption on organic farms for olive and citrus production, both with regard to energy... 

Uses. Linalyl acetate is used extensively in perfumery. It is an excellent fragrance material for, among others, bergamot, lilac, lavender, linden, neroli, ylang-ylang, and phantasy notes (particularly chypre). Smaller amounts are used in other citrus products. Since linalyl acetate is fairly stable toward alkali, it can also be employed in soaps and detergents. 

The clinical relevance of data obtained from studies with single compounds is questionable, because most studies were performed in in vitro systems, limiting the predictability of the effects of the examined compounds in vivo. Moreover, some polyphenolics, such as quercetin, were shown to interact with the absorption or metabolism of drugs only at very high concentrations (50-100 pmol/L), which are likely to exceed the expected in vivo concentration after the consumption of a moderate amount of a grapefruit/ citrus product. Also, flavonoids have been demonstrated to potentially induce apoptosis in cell lines at concentrations comparable to those used for some in vitro drug interaction studies (64-66). This potentially could have impaired the investigation of enzyme and transporter activities. 

According to the current, still limited knowledge, responsible recommendations should be communicated effectively to health care personnel and patients. Here care must be taken to avoid careless prescription of susceptible drugs without unnecessary overreaction leading to complete avoidance of citrus products, because these contain significant amounts of antioxidant phytochemicals with significant health benefits. 

RL Rouseff. Post-column derivatization in liquid chromatographic analysis of citrus products. Food Technol 39 87-90, 1985. 

For hydroxycinnamic acid derivatives in citrus products, an HPLC method was also applied to determine the hydroxycinnamic acid esters with glucose or aldaric acids in the peel and pulp... 

Comminutes. The process of comminution refers only to citrus products, where the oils that reside in the flavedo (coloured peel) have intense flavour characteristics. At its simplest, comminution involves taking a complete orange (or other citrus fruit) and making a pulp from it. This pulp will have a much more intense flavour than juice alone but because of the presence of much peel and albedo (pith) it would be unacceptable in taste to most consumers. Thus, the process of comminute production, developed in the immediate postwar years, is typically as set out in Figure 6.1. 

The energy-supplying nutrients are generally carbohydrates, protein and fat. While citrus products provide little protein and fat, their contribution of carbohydrate is an essential part of the nutritive value of citrus. The proximate composition of several kinds of citrus fruits (8) are shown in Table II. Because... 

Nearly 3/4 of all vitamin C in an orange and 5/6 in a grapefruit is found in the peel (56b however, citrus juices and their products provide a major portion of the vitamin C in the American diet. Considerable variations in vitamin C content can be found in different citrus products due to such factors as varietys, maturity and cultural practices of the fruit (57J from which the products originate and to the processing practices and storage conditions of these products before they reach the consumer. 

The ease of oxidation of reduced ascorbic acid is the basis for a simple method of analysis by dye titration (58j. Ascorbic acid as it occurs in citrus juice is in the reduced form. When subjected to oxidation, ascorbic acid changes to the dehydro form. Dehydroascorbic acid has nearly the same physiological activity as the reduced form and is easily converted to the latter. Further oxidation of the dehydroascorbic acid converts it to 2,3-diketo-gulonic acid. This reaction is irreversible, and the oxidized product is devoid of biological activity. These reactions are shown in Figure 2. Nearly 90 percent or more of the vitamin C found in citrus juice and citrus products is in the reduced form (Table X) (59). 

Table X. Reduced Ascorbic Acid and Dehydroascorbic Acid in Citrus Products...

Thiamine (Vitamin B.). Citrus products are also good sources of thiamine. They proviae comparable amount or more of vitamin B, than foods that are known suppliers of this nutrient on the basis of nutrient density as measured by the Index of Nutrient Quality (INQ) (64). Listed in Table XI are the INQ of some common foods. The vegetables have high INQ since the index is calculated on unit nutrient per KCal, but citrus products are higher in INQ than some other fruits. Wholewheat bread, usually considered as a source of vitamin B. has an INQ much lower than that of orange juice. Thiamine in canned orange juice is rather stable. 

Table XI. Comparison of Index of Nutrient Quality (INQ) of the Amino Acids of Citrus Products With Those of Various Other Common Foods ...

Potassium and Sodium. Potassium is the most abundant mineral of citrus juices and other citrus products, amounting to 40 percent of the total ash (73). In contrast, citrus fruits are low in sodium, generally less than 1 mg/100 ml juice (74). In 100 ml of orange juice, 4 to 6 meq of potassium may be available (73). Slightly less was found in canned grapefruit juice (72). 

These minerals are all found to be near, or slightly above, the caloric contribution of the citrus products (7, 75). 

Florida Department of Citrus, Standards for Processed Citrus Products, 1979 Section 20-64.03, 20-64.09. 

Bitterness is a generally undesirable flavor component and is usually detrimental to the quality of citrus products. Any bitterness in orange or tangerine products reduces their quality, whereas, a little bitterness is actually desirable for grapefruit products. However, it has been shown (35) that as the concentration of bitter materials increase, flavor scores and overall product acceptability decrease. Thus, excessive bitterness is usually considered objectionable and the Florida Department of Citrus has enacted regulations which limit the amount of naringin which may be present during the early weeks of the season (36). 

Gel formation by pectins can be a positive quality factor in some citrus products, for example, gelled citrus salads... 

Hasegawa, S. Brewster, L. C. Maier, V. P. Use of limonoate dehydrogenase of Arthrobacter globiformis for the prevention or removal of limonin bitterness in citrus products. J. Food Sci., 1973, 38, 1153-1155. 

Processed Florida Citrus Products 6-Year Average 1973-1978 (JL)... 

The contribution of lipid oxidative products to off-flavor development has been studied by many workers, and a review of these studies has been presented by Nagy (38). It is generally agreed that the contribution of the lipid oxidative products to the flavor deterioration of processed citrus products is relatively minor when compared to the contributions by the products formed by the acid-catalyzed hydrolysis of flavoring oils and the products of Maillard browning (39,40). 

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