Honey, organic acids

The amount of organic acids in honey is less than 0.5%. Organic acids can be used as an important indicator of organoleptic properties like color and flavor and physical and chemical properties such as pH, acidity, and electrical conductivity (Crane, 1990). The organic acids in honey also have antibacterial and antioxidant activities (Gheldof et ah, 2002 Weston et ah, 1998). Organic acids in honey can be used as fermentation indicators, or for the treatment of Varroa mite infestation (Calderone, 2000 Mutinelli et ah, 1997) and discriminating between honeys based on their... 

In general, CE is simple, rapid, and low cost because it needs neither laborious treatment of the samples nor long times of analysis. However, its high detection limit is a major limitation of CE. CE is often poorly reproducible. Enzymatic assay is more suitable for quantifying one organic acid in honey samples because it is specific, precise, and accurate. GC is more suitable for analyzing volatile or semivolatile chemicals. HPLC is versatile and reproducible. However, common HPLC detectors such as UV-VIS are not very sensitive for organic aliphatic acids. 

Cherchi, A., Spanedda, L., Tuberoso, C., and Cabras, P. (1994). Solid phase extraction and high-performance liquid chromatographic determination of organic acids in honey. 

Del Nozal, M. J., Bernal, J. L., Diego, J. C., Gomez, L. A., and Higes, M. (2003a). HPLC determination of low molecular weight organic acids in honey with series-coupled ion-exdusion columns. /. Liq. Chromatogr. Relat. Technol. 26,1231-1253. 

Echigo, T. and Takenaka, T. (1974). Production of organic acids in honey by honeybees. Nippon Nogei Kagaku Kaishi 48,225-230. 

Mato, 1., Huidobro, J. F., Simal-Lozano, J., and Sancho, M. T. (2003). Significance of non aromatic organic acids in honey. /. Food Prot. 66, 2371-2376. 

Pilz-Giither, D. and Speer, K. (2004). Development of a GC method for the simultaneous determination of organic acids in honey. Dtsch. Lebensm. Rundsch. 100,84-87. 

Tourn, M. L., Lombard, A., Belliardo, F., and Buffa, M. (1980). Quantitative analysis of carbohydrates and organic acids in honeydew, honey and royal jelly by enzymic methods. J. Apicult. Res. 19,144 146. 

In summary, although these organic acids are natural honey constituents, the international food legislation prohibits honey additives adulterating its taste. Therefore, the residues of these substances in honey have to remain below their taste threshold [35],... 

Honey composition varies, depending on floral origin, the climate, environmental and seasonal conditions, as well as agricultural practices (Al-Mamary et al., 2002 Anklam, 1998 Arraez-Roman et al., 2006 Azeredo et al., 2003 Baltrusaityte et al., 2007 Kii iik et al., 2007). Honey contains about 200 different substances (Al-Mamary et al., 2002 Arraez-Roman et al., 2006 Kiigiik et al., 2007), carbohydrates being the main constituents, followed by the minerals, proteins, vitamins, lipids, organic acids, amino acids (Finola et al., 2007), phenolic compounds (flavonoids and phenolic acids), and other phytochemicals (Bertoncelj et al., 2007). 

Organic acids are responsible for the acidity of honey and contribute considerably to its unique flavor (Anklam, 1998). Organic acid content of about 0.57% consists primarily of gluconic acid. It is a by-product of the enzymatic action of glucose oxidase on glucose (Olaitan et ah, 2007). Other organic acids identified up to the present are the pyruvic acid, malic acid, citric acid, succinic acid, and fumaric acid. 

The pH of honey ranges between 3.4 and 6.1 with an average of 3.9 (Iurlina and Fritz, 2005). However, the pH is not directly related to acidity, due to the buffering action of acids and minerals found in honey (de Rodriguez et ah, 2004). Its acidity is due to the presence of organic acids, particularly gluconic acid, pyruvic acid, malic acid, and citric acid. These are in equilibrium with lactones or esters, as well as to inorganic ions, such as, phosphate or chloride (Anklam, 1998). 

Electrical conductivity is directly related to the concentration of mineral salts, organic acids, and proteins and may be useful in identifying floral origin (Acquarone et al., 2007). Honeydew honeys should register... 

The chemical composition of honey (Table 2.3) is dominated by glucose and fructose. Honey also contains many other valuable components, like enzymes, organic acids, mineral elements, nonprotein nitrogenous compounds, vitamins, aroma substances, and pigments. 

The natural occurrence of varying amounts of organic acids in honeys from different geographical areas have been documented. Much research is being done to determine the use of honey as an antimicrobial agent in various food systems (Suarez-Luque et al., 2002). 

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