Validation of Folate-Enriched Eggs as a Functional Food for Improving Folate Intake in Consumers

Abstract

Functional foods enriched with folate may be beneficial as a means of optimizing folate status in consumers. We recently developed novel eggs enriched with folate through folic acid supplementation of the hen’s feed, but their potential to influence consumer folate status is unknown because the natural folate forms incorporated into the eggs may not necessarily be retained during storage and cooking. This study aimed to determine the stability of natural folates in folate-enriched eggs under typical conditions of storage and cooking. Total folate was determined by microbiological assay following tri-enzyme treatment in folate-enriched eggs and un-enriched (barn and free-range) on the day they were laid, after storage (up to 27 days) and after using four typical cooking methods (boiling, poaching, frying, scrambling) for different durations. On the day of laying, the folate content of enriched eggs was found to be significantly higher than that of un-enriched barn or free-range eggs (mean ± SD; 123.2 ± 12.4 vs. 41.2 ± 2.8 vs. 65.6 ± 18.5 µg/100 g; p < 0.001). Storage at refrigerator and room temperature for periods up to the Best Before date resulted in no significant losses to the folate content of folate-enriched eggs. Furthermore, folate in enriched eggs remained stable when cooked by four typical methods for periods up to the maximum cooking time (e.g., 135 ± 22.5, 133.9 ± 23.0 and 132.5 ± 35.1; p = 0.73, for raw, scrambled for 50 s and scrambled for 2 min, respectively). Thus, natural folates in folate-enriched eggs remain highly stable with little or no losses following storage and cooking. These findings are important because they demonstrate the feasibility of introducing folate-enriched eggs into the diet of consumers as functional foods with enriched folate content. Further studies will confirm their effectiveness in optimizing the biomarker folate status of consumers.

Folate Content and Yolk Color of Hen Eggs from Different Farming Systems

“…The results obtained for organic eggs correspond well to the values presented for eggs of unknown origin by Soongsongkiat et al (117 µg/100 g) [42] and Yon et al [43] (114 µg/100 g). Organic eggs from our study showed folate levels (93.7-142.8) comparable those found in folate-enriched free-range eggs reported by Altic et al [21] (123.2 µg/100 g). These authors found the total folate content in un-enriched barn and un-enriched freerange eggs at the much lower levels, i.e., 41.4 and 65.6 µg/100 g, respectively, compared to our results for eggs from the same farming system.…”

“…These authors found the total folate content in un-enriched barn and un-enriched free-range eggs at the much lower levels, i.e., 41.4 and 65.6 µg/100 g, respectively, compared to our results for eggs from the same farming system. The difference observed in folate content between eggs from these two rearing systems was explained by Altic et al [ 21 ] by the fact that free range hens have access to the fresh forage and this can provide an extra folate source to their daily feed. Barn hens are only fed with processed feed, probably low in folates.…”

“…However, due to health risks posed by the chronic exposure of the entire population to the synthetic form of the vitamin (folic acid), which can lead to the presence of unmetabolized folic acid in the organism, whose role remains unknown, no obligation to fortify food with folic acid has been introduced in any European country. The most frequently used argument against the regulation is the possibility of masking the macrocytic anemia of vitamin B12 deficiency in the elderly consuming high doses of folic acid [ 18 , 19 , 20 , 21 ]. Another reason for not choosing the mandatory folic acid fortification is the failure of clinical trials to prove its expected additional health benefits for the general population and not just for women of the childbearing age before conception.…”

“…Limited information on folate content in eggs, which are reported to have the potential to improve folate supply, have prompted us to deliver basic knowledge in this field. While the previous research concerned mainly eggs from laying hen farms with known [ 34 ] and specially developed feeding [ 21 ], the aim of this study was to evaluate the folate content in eggs from different rearing systems (organic, free barn, barn, and cage) obtained as they would be bought by consumers from the local market on their daily routine. A second objective was to present the distribution of different folate vitamers and their stability under cooking because most of the available data provide only the total folate content.…”

Time Trends and Patterns of Reported Egg Consumption in the U.S. by Sociodemographic Characteristics

“…Continued advancements in nutrient-enriched eggs (for example, eggs high in α-linolenic acid and docosahexaenoic acid [ 44 ], folate [ 45 ], iodine [ 46 ], and some lipophilic antioxidants [ 47 ]) may appeal to some consumer segments. Yet the potential market for these specialty products is not well understood, and their production partly depends on the availability of specific poultry feed formulations and supply chain infrastructure, and is complicated by the recent downsizing of poultry flocks noted above.…”