Eric T. Gugger

The crystalline form of carotenes and the food matrix in carrot root decrease the relative bioavailability of beta- and alpha-carotene in the ferret model.

OBJECTIVE The objective of this study was to investigate the relative bioavailability (BV) of beta-carotene (BC) and alpha-carotene (AC) from different extracts of carrots utilizing the ferret model. METHODS Five groups of animals (n = 6) were provided free access to a carotenoid-free, vitamin A-adequate diet and tap water for 2 weeks, then for 3 consecutive days 10 mg of BC was provided in 30--40 mL of one of the following fluids as partial replacement for tap water along with diet: 1) commercial BC beadlets dispersed in distilled water (control), 2) non-heated carrot juice, 3) heated carrot juice, 4) non-heated isolated carrot chromoplasts, or 5) heated carrot chromoplasts. The animals were killed and samples of blood and tissues (liver, adrenal, lung, kidney, spleen) were collected and analyzed for AC and BC concentrations. RESULTS The tissue analysis of BC concentrations indicated that BC-beadlet-supplemented animals had significantly higher BC concentrations than other groups (p<0.01). Carrot chromoplast-supplemented animals had significantly higher tissue BC and AC concentrations than carrot juice-supplemented animals. Heat treatment tended to reduce the relative BV of carotenoids but the differences between heated and non-heated juices or isolated carrot chromoplasts were not significantly different. CONCLUSIONS These results suggest that the food matrix, probably pectin-like fibers, and the crystalline form of carotenoids in carrot chromoplast are the primary factors that reduce the relative BV of carotenoids from carrot juice.

Analysis of carotenoids in human and animal tissues.

Publisher Summary This chapter describes the extraction of carotenoids from human and animal tissues and subsequent analysis using high-performance liquid chromatography (HPLC). The identification and quantitation of carotenoids are routinely accomplished for many types of plant tissues using HPLC techniques, and careful examination of these methods is helpful in developing approaches to analyze human and animal tissues for carotenoids. An accurate qualitative and quantitative analysis of carotenoids present in human and animal tissues is dependent on the careful selection of extraction and analytical procedures. Strict adherence to laboratory protocol, which minimizes degradation and/or isomerization of carotenoids during both extraction and analysis procedures, should be observed to ensure accurate results. The procedures and modifications presented in the chapter provide a method by which the major carotenoids present in human and animal tissues may be accurately identified and quantified.

The relationship between plasma, leukocyte and leukocyte membrane beta-carotene concentrations in bovine animals

Abstract Blood was obtained at the time of slaughter from 14 mature bovine animals. Plasma, leukocyte and leukocyte membranes were harvested from each blood sample and beta-carotene concentrations were determined. Plasma beta-carotene concentrations ranged from 32.4 to 115.5 nmoles/dl (17.4 to 62.0 ug/dl) with a mean concentration of 73.2 nmoles/dl (39.3 ug/dl). Whole leukocyte beta-carotene concentrations in these same animals ranged from 0.07 to 0.31 nmoles/g weight (mean=0.17 nmoles/g). Leukocyte membrane beta-carotene concentrations ranged from 0.74 pmole/g to 0.29 n mole/g (mean 0.15 nmole/g). There was a linear relationship between plasma and leukocyte beta-carotene concentrations with a correlation coefficient of .82. A linear relationship also existed between plasma and leukocyte membrane beta-carotene concentrations (correlation coefficient=.78) and between leukocyte and leukocyte membrane beta-carotene concentrations (correlation coefficient=.65). Thus, beta-carotene is present in bovine leukocyte and leukocyte membranes and a linear relationship exists between plasma levels and beta-carotene content in these cells and cell membranes.