Yogurt Enriched with Isochrysis galbana: An Innovative Functional Food.

Joana Matos,Cláudia Afonso,Carlos Cardoso,Maria L Serralheiro,Narcisa M Bandarra

doi:10.3390/foods10071458

Abstract

Microalgae are a valuable and innovative emerging source of natural nutrients and bioactive compounds that can be used as functional ingredients in order to increase the nutritional value of foods to improve human health and to prevent disease. The marine microalga Isochrysis galbana has great potential for the food industry as a functional ingredient, given its richness in ω3 long chain-polyunsaturated fatty acids (LC-PUFAs), with high contents of oleic, linoleic, alpha-linolenic acid (ALA), stearidonic, and docosahexaenoic (DHA) acids. This study focuses on the formulation of a functional food by the incorporation of 2% (w/w) of I. galbana freeze-dried biomass and 2% (w/w) of I. galbana ethyl acetate lipidic extract in solid natural yogurts preparation. In the functional yogurt enriched with microalgal biomass, the ω3 LC-PUFA’s content increased (to 60 mg/100 g w/w), specifically the DHA content (9.6 mg/100 g ww), and the ω3/ω6 ratio (augmented to 0.8). The in vitro digestion study showed a poor bioaccessibility of essential ω3 LC-PUFAs, wherein linoleic acid (18:2 ω6) presented a bioaccessibility inferior to 10% and no DHA or eicosapentaenoic acid (EPA) was detected in the bioaccessible fraction of the functional yogurts, thus indicating a low accessibility of lipids during digestion. Notwithstanding, when compared to the original yogurt, an added value novel functional yogurt with DHA and a higher ω3 LC-PUFAs content was obtained. The functional yogurt enriched with I. galbana can be considered important from a nutritional point of view and a suitable source of essential FAs in the human diet. However, this needs further confirmation, entailing additional investigation into bioavailability through in vivo assays.

Highlights

Nowadays, consumers have become more conscious about food ingredients, which has led to a growing demand for healthy natural products, and reinforced microalgae as an emerging and rich source of nutrients to be used in food supplementation [1]
The obtained results show the potential of incorporating the microalga I. galbana freezedried biomass as a functional ingredient into yogurts, wherein ω3 LC-polyunsaturated fatty acids (PUFAs) content was enhanced (60 mg/100 g ww), concerning DHA (9.6 mg/100 g ww), and the ω3/ω6 ratio rose to 0.8
The incorporation of I. galbana freeze-dried biomass in yogurts was shown to be more effective in enhancing ω3 LC-PUFAs content than the ethyl acetate extract incorporation, which means that the green solvent lipid extraction from I. galbana was not as effective as expected

Summary

Introduction

Consumers have become more conscious about food ingredients, which has led to a growing demand for healthy natural products, and reinforced microalgae as an emerging and rich source of nutrients to be used in food supplementation [1]. There has been an increasing interest in ω3 long-chain (LC) polyunsaturated fatty acids (PUFAs) for nutritional and pharmaceutical applications. The nutritional importance of ω3 LC-PUFAs, mainly eicosapentaenoic acid (EPA, 20:5 ω3) and docosahexaenoic acid (DHA, 22:6 ω3), for human health is well established. Since humans cannot synthesize, in adequate levels, fatty acids with more than 18 carbons, they must be obtained from seafood, which is the major source of LC-PUFAs, EPA and DHA [2]. Several studies have shown that EPA and DHA play an important role in the functional growth of brain cells, in preventing/reducing cardiovascular and inflammatory diseases, and in preventing the progression of some types of cancer [1,2,3,4,5]. DHA has been associated with positive effects on memory-related learning ability in Alzheimer’s disease [4,6]

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