Steven Nagy

Methods for determining the adulteration of citrus juices

The adulteration of fruit juices and juice-based beverages is a serious economic problem. Juice adulteration has progressed from simple dilution with water and the substitution of cheap ingredients to highly sophisticated manipulations designed to mask the adulteration process. Major adulteration problems currently encountered by regulatory agencies include undeclared addition of sugar and pulp wash, the admixture of juices, and the addition of colorants, amino acids and organic acids. Also of regulatory concern is ascertaining the geographical origin of a juice. While numerous methods have been developed to detect juice adulteration, only a limited number have proved workable in deterring sophisticated adulteration. Methodologies critically evaluated in this report include isotopic analyses, SNIF-NMR, HPLC, tracer addition, UV/VIS spectrophotometry, ICP-AES, electrochemical detection and pattern recognition.

Application of pattern recognition techniques to sensory and gas chromatographic flavor profiles of natural orange aroma

Abstract Meaningful analysis of citrus aroma required a multidimensional approach. First, organoleptic evaluation provided information on the product that could be equated to consumer acceptability. Secondly, gas chromatographic-mass spectral analysis yielded both identity and quantitation of the aroma constituents. Thirdly, computational profiling of organoleptic data and instrumental data were used to construct multidimensional plots that separated samples with different compositions and flavor attributes into several categories. Quantitative descriptive analysis (QDA) utilizing linear numerical scores were used to quantify 12 aromatic descriptors, and various pattern recognition routines of ARTHUR were applied to evaluate the data. A panel separated samples into categories described as fruity, fresh orange-like, flowery herbal-like, butter oil-like, pepper-like and fruity tea-like. Data treatment, depicted by nonlinear mapping (NLM), resolved these samples into categories with differing off-flavor and non-off-flavor attributes. Feature weightings (variance and Fisher) indicated that the descriptor ‘overall quality’ had the most discriminating power for sensory evaluation of good quality aroma samples. A separate ARTHUR analysis of gas chromatographic data clearly separated aroma samples into groupings that were related to the categories previously separated by an aroma panel and depicted by NLM. Ethyl acetate, acetal and ethyl butyrate were high variance- and Fisher-weighted GC features.

Chemotaxonomic study of neutral coumarins in roots of Citrus and Poncirus by thin-layer, gas-liquid and high-performance liquid chromatographic analyses

Abstract Eight neutral coumarins were isolted from the roots of 11 Citrus and Poncirus cultivars by thin-layer chromatography (TLC). These coumarins included seselin, xanthyletin, poncitrin, osthol, suberosin and xanthoxyletin. The two other were only tentatively identified. The eight were completely resolved by gas-liquid chromatography (GLC) with two different liquid phases. With limited studies these eight were not however, completely resolved by TLC or high-performance liquid chromatography (HPLC). Values from HPLC supported the quantitative values obtained by GLC. Profiles of these eight coumarins were intrinsic to Citrus and Poncirus species, with hybrids having profiles characteristic of both genera

HEALTH PROMOTING PHYTOCHEMICALS IN CITRUS FRUIT AND JUICE PRODUCTS

Citrus fruit and juice have long been traditional health-promoting foods. The origin of citrus is commonly thought to be in the southwest region of China, and citrus is at the very center of all Chinese traditional herbal medicine. All parts of the fruit are considered medicinal and wholesome, and this reputation has spread with citrus throughout the world. As modern science studies citrus more carefully, it seems that traditional beliefs may be founded in fact. Orange and grapefruit are excellent sources of Vitamin C, a good source of folic acid, and a fair source of niacin, and thiamine. Although the benefits of these constituents are too numerous to list in this publication, nutrition alone would be a compeUing reason to consume fresh citrus or drink juice. The vitamins are only part of the story, however. Virtually every class of phytochemical known can be found in relatively high concentration in citrus including flavonoids, triterpenes (sterols), hydroxycinnamic acids, polysaccharides (fiber), hexaric acids, monoterpenes, flavor and aroma molecules. In fact, when one drinks a glass of orange or grapefruit juice, there are more phytochemicals ingested by weight than vitamins. This review article is about these phytochemicals and their impact on mammalian and perhaps human health.