The Effects of Steaming on Color and Carotenoid Absorption Spectra of Orange-, Yellow- and Purple-Fleshed Sweet Potatoes (Ipomoea batatas (L.) Lamb.)

Sweet potatoes, especially the orange and yellow-fleshed, are functional local food because they contain carotenoids which serve as a pro-vitamin A. The processing of sweet potatoes into noodles, fermented cassava or “tape” and artificial rice is usually prepared through steaming. However, carotenoid is susceptible to degrade when it is subjected to high temperature, such as steaming. The objective of this research is to determine the effects of steaming on the color and carotenoid absorption spectra of local and excellent sweet potatoes which are correlated to the carotenoid content and to evaluate the difference of carotenoid spectral properties among sweet potatoes by principal component analysis (PCA). The steaming treatment decreased color values, such as lightness, redness, and yellowness. In addition, this process also influenced the spectral properties of carotenoid extracts of sweet potatoes. Steaming decreased absorbance and resulted in hypsochromic and bathochromic shifts. Madu Mojokerto, Manohara, local purple fleshed, Beta 1, and Papua Solossa sweet potatoes experienced some decreases in absorbance and a hypsochromic shift of ± 77 % and ± 2 nm, ± 40 % and ± 21 nm, ± 63 % and ± 28 nm, ± 44 % and ± 2 nm, and ± 20 % and ± 23 nm, respectively; while Antin 3 sweet potatoes experienced some decrease in absorbance of ± 36 % and a bathochromic shift of ± 28 nm. The PCA results showed that there were four groups of sweet potatoes based on spectrum shape and absorbance value.

The ways and means of Express-diagnostics of plants for protected ground

The article deals with the results of studies related to the testing of the proposed method of rapid diagnosis of plants conducted in the production conditions of Agrocomplex "Churilovo". It was found that the absorption spectrum of the leaf apparatus of cucumber plants in the control variant (substrate – mineral wool) and the experimental variant (substrate - agroperlite) differed insignificantly: the arithmetic mean values of chlorophyll absorption in the control and experiment were 3,668 and 3,772, respectively; carotenoid absorption - 3,560 and 3,403; cytochrome absorption - 2,681 and 2,645, respectively. There were minor differences in the content of micro - and macronutrients in plant leaves and yield. It is revealed that the proposed method of rapid diagnosis, based on the analysis of the absorption spectra of the sheet apparatus, allows to obtain results comparable to the results of chemical analysis and yield assessment, and can be used to diagnose the condition of plants.

Mechanisms of Carotenoid Intestinal Absorption: Where Do We Stand?

A growing literature is dedicated to the understanding of carotenoid beneficial health effects. However, the absorption process of this broad family of molecules is still poorly understood. These highly lipophilic plant metabolites are usually weakly absorbed. It was long believed that β-carotene absorption (the principal provitamin A carotenoid in the human diet), and thus all other carotenoid absorption, was driven by passive diffusion through the brush border of the enterocytes. The identification of transporters able to facilitate carotenoid uptake by the enterocytes has challenged established statements. After a brief overview of carotenoid metabolism in the human upper gastrointestinal tract, a focus will be put on the identified proteins participating in the transport and the metabolism of carotenoids in intestinal cells and the regulation of these processes. Further progress in the understanding of the molecular mechanisms regulating carotenoid intestinal absorption is still required to optimize their bioavailability and, thus, their health effects.

No influence of supplemental dietary calcium intake on the bioavailability of spinach carotenoids in humans

Dietary carotenoid intake, especially from fruits and vegetables, has been associated with a reduced incidence of several chronic diseases. However, its bioavailability can vary, depending on the food matrix and host factors. Recently, it has been suggested that divalent minerals negatively impinge on carotenoid bioavailability by reducing bile-salt and non-esterified fatty-acid levels in the gut, which normally aid in emulsifying carotenoids. The aim of the present study was to investigate whether supplemental Ca would negatively influence carotenoid absorption in humans. A total of twenty-five healthy, non-obese men (age: 20–46 years, BMI<30 kg/m2) were recruited for this postprandial, randomised, crossover, double-blinded trial. Following a randomised block design, each participant received (after 2-week washout periods), on three occasions separated by 1 week, 270 g of spinach-based meals (8·61 (sd 1·08) mg carotenoids/100 g fresh weight), supplemented with 0, 500 or 1000 mg of Ca (as calcium carbonate), with each participant acting as his or her own control. Blood samples were collected at regular postprandial intervals for up to 10 h following test meal intake, and standardised lunches were served. TAG-rich lipoprotein fractions were separated and carotenoid concentrations determined. AUC for meals without supplemented Ca were 22·72 (sem 2·78) nmol×h/l (lutein), 0·19 (sem 3·90) nmol×h/l (β-carotene) and 2·80 (sem 1·75) nmol×h/l (β-cryptoxanthin). No significant influence of supplementation with either 500 or 1000 mg of supplemental Ca was found. In conclusion, Ca – the most abundant divalent mineral in the diet – given at high but physiological concentrations, does not appear to have repercussions on the bioavailability of carotenoids from a spinach-based meal.