Egg Yolk Carotenoids: Composition, Analysis, and Effects of Processing on Their Stability. In: Winterhalter P, Ebeler SE, editors. Carotenoid Cleavage Products. Washington: American Chemical Society; 2013. pp. 219-25. [DOI: 10.1021/bk-2013-1134.ch018]

A critical insight into the physicochemical stability of macular carotenoids with respect to their industrial production, safety profile, targeted tissue delivery, and bioavailability

Lutein, zeaxanthin, and mesozeaxanthin, collectively termed as macular pigments, are key carotenoids integral to optimized central vision of the eye. Therefore, nutraceuticals and functional foods have been developed commercially using carotenoid rich flowers, such as marigold and calendula or single celled photosynthetic algae, such as the Dunaliella. Industrial formulation of such products enriched in macular pigments have often suffered from serious bottlenecks in stability, delivery, and bioavailability. The two chief factors largely responsible for decreasing the shelf-life have been solubility and oxidation of these pigments owing to their strong lipophilic nature and presence of conjugated double bonds. In this regard, oil-based formulations have often been found to be more suitable than powder-based formulations in terms of shelf life and targeted delivery. In some cases, addition of phenolic acids in the formulations have also augmented the product value by enhancing micellization. In this regard, a novel proprietary formulation of these pigments has been developed in our laboratory utilizing marigold extracts in a colloidal solution of extra virgin olive oil and canola oil fortified with antioxidants like thyme oil, tocopherol, and ascorbyl palmitate. This review article presents an updated insight into the stability and bioavailability of industrially manufactured macular carotenoids together with their safety and solubility issues.

The Effects of Dietary Inclusion of Bilberry and Walnut Leaves in Laying Hens' Diets on the Antioxidant Properties of Eggs

Simple Summary

Eggs are considered common dietary sources of n-3 polyunsaturated fatty acids (PUFA), but they are susceptible to quality deterioration. In order to reduce oxidation, the best strategy is the addition of antioxidants to hens’ diets. Walnut and bilberry co-products, rich in phenolic compounds, are produced in agricultural industries, and are a valuable source of antioxidants for animal nutrition. The dietary inclusion of bilberry and walnut leaves as natural sources of antioxidants in poultry diets led to the accumulation of nutrients with antioxidant activity in the egg yolk, and the susceptibility of the yolk to lipid peroxidation during storage improved. The results of the present study showed that including bilberry and walnut leaves in laying hens’ diets enhanced the oxidative stability of the egg yolk and retarded the lipid peroxidation process during storage.

Abstract

The purpose of this study was to examine the effects of dietary inclusion of walnut and bilberry leaves (WL and BL), as sources of natural antioxidants in poultry diets, on the enrichment of antioxidant nutrients in the egg yolk and on the susceptibility of the yolk to lipid peroxidation during storage. The experiment was conducted on 32-week-old TETRA SL LL laying hens, which were assigned to three dietary treatments with 30 birds each. Each treatment was replicated 10 times with three chicks per replicate pen. Experimental dietary treatments differed from control diet (C) by addition of 0.5% BL supplement or 1% WL supplement. The phytoadditives were not significant contributors to the productive parameters. The addition of BL and WL in laying hens’ diets significantly increased the total polyphenol content, and the zinc, lutein and zeaxanthin concentrations in the egg yolks. In regards to the oxidative stability parameters, a significant decrease in the concentrations of primary oxidation products formed in the egg yolk of experimental groups was seen, proving an efficient inhibition effect of the phytoadditives on peroxyl radical formation. A significant correlation was observed between primary oxidation products and total polyphenol content of the egg yolks, where zinc, lutein and zeaxanthin are the bioactive compounds that inhibit the formation of secondary oxidation products.

Production of single cell protein from manure as animal feed by using photosynthetic bacteria

To reduce the cost of protein feedstock for animal feed, the use of single cell protein (SCP) produced from waste of animal agriculture is an interesting choice. This study reveals that chicken manure was the best substrate for SCP production by submerged fermentation using photosynthetic bacteria compared to swine, cow, and buffalo manure. Regression analysis showed that the productions were found to be significantly influenced by chicken manure content, inoculum size, and cultivation time. Response surface methodology based on central composite design generated the optimal condition (15% chicken manure, 30% inoculum size and cultivation time for 14 days) at which biomass, protein, and carotenoid productions were increased by 92.3%, 21.6%, and 18.2%, respectively. The percentage of error between the predicted and actual values for biomass, protein, and carotenoid productions were 1.56%, 2.64%, and 2.09%, respectively, which indicates the precision of the model. To verify the quality of SCP, the bacterium was cultured in a photobioreactor to investigate amino acid composition, protein, and nucleic acid contents. The SCP yielded 62.7% protein with essential amino acids including lysine, methionine, threonine, phenylalanine, leucine, isoleucine, valine, histidine, and low nucleic acid content of 4.52%. This study suggests an alternative SCP production for animal feed as well as the strategy for animal waste management.

Composition of Lutein Ester Regioisomers in Marigold Flower, Dietary Supplement, and Herbal Tea

Characterization of lutein and its esters in a health product is necessary for its efficacy. In the current study lutein ester regioisomers were quantified and identified in several dietary supplements and herbal teas in comparison with marigold flower, the commercial source of lutein. The products were extracted with three solvents and separated on a C30 column. The separated esters were identified/confirmed with LC-MS in APCI+ve mode with the use of synthetic lutein esters. The total content of lutein esters substantially varied among marigold flowers (167-5752 μg/g), supplements (88,000-110,700 μg/g), and herbal teas (12.4-91.3 μg/g). Lutein supplement had a lutein profile similar to that of marigold flower, whereas herbal tea showed an extremely different profile. Lutein dipalmitate was the dominant compound in supplements and marigold flowers followed by lutein 3'-O-myristate-3-O-palmitate and lutein 3'-O-palmitate-3-O-myristate. Lutein was the major compound in marigold herbal tea with small amounts of lutein mono- and diesters. Differences in the concentration and composition of lutein compounds among marigold products could indicate distinct product quality and lutein bioavailability.