Citrus Limonoids: Functional Chemicals in Agriculture and Foods

The search for limonoids started long back when scientists started looking for the factor responsible for bitterness in citrus. Studies showed that limonoids are highly oxygenated, modified terpenoids and have recently attracted attention because compounds belonging to this group have exhibited a range of biological activities like insecticidal, insect antifeedant and growth regulating activity on insects as well as antibacterial, antifungal, antimalarial, anticancer, antiviral and a number of other pharmacological activities on humans. Based on this premise this paper has focused on technological, healthful and chemical aspects of the limonoids. -TECHNOLOGICAL APPROACH: Based on a project titled Enhancement of bioactive compounds isolated from agro-industrial wastes financially supported by the Italian Ministry of Education, a Sicilian juice company wanted to assess the possibility of transforming the waste by-product of citrus processing (pastazzo) in a resource trying to turn it into dietary fiber. To do that, the company has inserted a debittering line to the plant using an alkaline aqueous solution in order to extract flavanones and limonoids. In the present paper the operational conditions of debittering were evaluated and optimized by determining the limonin content of samples from various stages of fiber production; It was also verified if the recovery of limonin extracted was economically viable. -HEALTHFUL AND ORGANOLEPTIC CHARACTERISTICS: It has been established that U.S. producers are turning to organic farming system as a potential way to lower input costs, decrease reliance on nonrenewable resources, capture high-value markets at premium price, and boost-farm income. Organic production agriculture is characterized by inputs of biologically (non-synthetic) based fertilizers and pest management practices that are sustainable. In order to understand if the market source contributes to differences in bioactives content, the bio-actives content of fruits obtained from farmers' markets was compared to the content found in fruit purchased from retail grocery stores. Organoleptic properties, including Brix, TTA, color and pH were measured. Limonin, ascorbic acid and flavanoid contents were also determined. -SYNTHESIS AND CHARACTERIZATION OF FUNCTIONAL COMPOUNDS: Ehrlich s reagent, p-dimethylaminobenzaldehyde (DMBA) in hydrochloric acid, has a long history and is known as the coloring reagent of pyrrole. 2,3. When a solution of limonoids is treated with p-dimethylaminobenzaldehyde in acid environment the solution immediately change to red-purple until dark blue. This reaction has named Ehrlich s reaction and the purple coloring is probably due to the presence of an adduct compound with an electron-rich trisubstituted furan ring. In order to determine the structure of the limonin-DMBA and limonin glucoside-DMBA adducts, both compounds have been synthesized, purified and characterized. This project involves synthesis of the target compounds. MS analysis were conducted for the characterization of the isolated products.