Juices organic acids

Fruit and vegetable juices packed with 21-26 in. of vacuum and stored in uncoated aluminum cans caused severe corrosion as shown in Table III. The corrosion rate brought about by the juices depends more on the nature of the organic acid present and the buffering capacity of the juice than on the total titratable acidity (11). The use of coated aluminum containers considerably minimized corrosion problems. Product control under extended storage conditions may be achieved by using specific chemical additives. However, more work is needed in this area before final conclusions can be reached. 

The complexity of wine composition is a central reason for the vast variety of wines in the marketplace. In addition to water and ethanol, the major components, a variety of organic acids as well as metal ions from minerals in the skin of the grape are present. Initially, all of these substances remain dissolved in the bottled grape juice. As the fermentation process occurs, the increasing alcohol concentration in the wine alters the solubility of particular combinations of acid and metal ions. Unable to remain in solution, the insoluble substances settle as crystals. Since the process of red-wine making involves extended contact of the grape juice with the skins of the grapes (where the minerals are concentrated), wine crystals are more common in red wines than in white wines. 

Organic acids Effective alone or on combination with other sanitizers, simple products such as lemon juice or vinegar may be used Not useful for all products, may have adverse effects on sensory qualities, may lead to loss of germination percentage when used on seeds... 

Chen et al. (1997a) analysed sodium saccharin in soft drinks, orange juice and lemon tea after filtration by injection into an ion-exclusion column with detection at 202 nm. Recoveries of 98-104% were obtained. They reported that common organic acids like citric and malic and other sweeteners did not interfere. Qu et al. (1999) determined aspartame in fruit juices, after degassing and dilution in water, by IC-PAD. The decomposition products of aspartame, aspartic acid and phenylanaline were separated and other sweeteners did not interfere. The recoveries of added aspartame were 77-94%. Chen et al. (1997b) separated and determined four artificial sweeteners and citric acid. 

G. Shui and L.P. Leong, Separation and determination of organic acids and phenolic compounds in fruit juices and drinks by high-performance liquid chromatography. J. Chromatogr.A 977 (2002) 89-96. 

The name, maleic anhydride, came about in the same fashion. as any number of compounds early in the petrochemical Business Many organic acids and their derivatives were given common names based on some early observations, their special source in nature, or on some special feature of their structure. MA was first isolated in the 1850—75 era by dehydration of malic acid, a sugar acid found in apple juice. The Latin word for apple is malum. Hence, malum, malic, maleic. The suffix, anhydride, which follows each alias of MA, has a simple definition a compound derived by the loss of a molecule of water from two carboxyl groups (-COOH). 

Fig. 8.5. HPLC chromatogram of a first-out silage juice using a Rezex ROA-organic acid column. Identity a, laotio aoid b, formic acid c, acetic acid d, propionic acid e, n-butyric acid f, 2-ethylbutyric acid (internal standard).

Elderberry (Sambucus nigra) is cultivated on small scale in Europe. The fruits have a high concentration of red and purple anthocyanins and a relatively low concentration of sugars, organic acids and aroma compounds, which make this juice attractive as a natural colour ingredient in other red fruit products [126-129]. The fresh green odour of elderberry juice is associated with volatile compounds with typical green notes such as 1-hexanol, 1-octanol, (Z)-3-hexen-l-ol, ( )-2-hexen-l-ol, hexanal and ( )-2-hexenal, whereas the floral aroma is mainly due to the presence of hotrienol and nonanal [127-130]. 

Sansevieria trifosciate Prain Hu Wei Lan (Snake plant) (leaf) Abamagenin, haemolytic sapogenin, organic acids.50 Leaf juice for earache. Treat itchiness. 

The term wine refers to the natural beverage produced from the juice of sound and ripe grapes, in strict accordance with federal and state regulations. The stabilization principles discussed will have equal application to fruit wines in general except for tartrate stabilization since tartaric acid, the primary organic acid of grapes, is not found in any other fruits commonly used in winemaking. 

Sample matrices with high levels of citric or other organic acids (e.g., cranberry juice) can result in poor resolution. This method of sample preparation isolates sugars (i.e., neutral compounds) from acids using anion-exchange mini-columns. Development of this protocol is based on research conducted by Hong and Wrolstad (1986). Although the procedure does require additional time (i.e., twelve samples per hour), it does result in improved resolution and a more stable baseline. 

For each sample type, a literature review must be done prior to analysis to determine the appropriate organic acids and their concentrations. Typical acids include acetic, butyric, citric, formic, hippuric, isobutyric, isovaleric, lactic, malic, oxalic, phenylacetic, propionic, pyruvic, tartaric, uric, and valeric acids. The recipe for organic acid standard solutions (see Reagents and Solutions) describes standards that can be used for a number of fruit juices. 

When analyzing drinking juices, correct for °Brix to relate the results to singlestrength juice using the equation CoBrix = Cs x (11.5/°Brix of sample), where CoBrix is the concentration of an organic acid in the sample at 11.5 °Brix. 

Table G2.2.2 Acid Concentrations (in g/liter) in Organic Acid Standards for Selected Juices...

Table G2.2.3 Concentrations of Organic Acids Commonly Found in Various Fruit Juices"... 

Coppola, E. and Star, M.S. 1986. Liquid chromatographic determination of major organic acids in apple juice and cranberry juice cocktail Collaborative study. J. Assoc. Off. Anal. Chem. 69 594-597. 

---