Temperature Effects on the Physicochemical Properties and Composition of Fatty Acids in the Oil of Chia Seeds

Temperature Effects on the Physicochemical Properties and Composition of Fatty Acids in the Oil of Chia Seeds

María Gabriela Vargas Martínez (Universidad Nacional Autónoma de México, Mexico), Selene Pascual-Bustamante (Universidad Nacional Autónoma de México, Mexico) and María del Carmen Beltrán-Orozco (Instituto Politécnico Nacional, Mexico)
DOI: 10.4018/978-1-7998-1518-1.ch010

Abstract

Chia seeds have a high content of omega 3, 6, and 9 fatty acids, so their consumption has become popular, often added to products subjected to heat treatments. This chapter evaluated the effect of temperature and time on the physicochemical properties and fatty acid composition of chia seed oil. The seeds, either whole or ground, were subjected to several treatments using a full factorial experimental design 32 where the factors were: the temperature (150, 187, and 225 °C) and treatment time (10, 25 and 40 min), while the studied responses were: iodine, acid, peroxide, and saponification values, Kreis test, and the content of omega 3, 6, and 9, the latter evaluated by gas chromatography. The use of moderate temperatures and short baking times is recommended (150 to 155 °C, less than 14 min) to avoid the loss in essential fatty acids and thus preserve the nutritional value of chia added in functional foods.
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Introduction

Salvia hispanica L. is a herbaceous plant of the family of the lamiaceae, native to southwestern Mexico and Guatemala. The seed is rich in mucilage, starch and oil. The commercial chia seed is approximately 2 mm long and 1.5 mm wide. They have a small oval or circular shape, which often varies in color from dark brown to black gray. It is also possible to find white chia seeds (cultivar) or very small brown seeds that are little-known Mexican varieties of local consumption (Ghill, 2003).

In the pre-Columbian cultures of Mesoamerica, the specie is known as “Chía” (Cahill, 2003). At the time of the Aztecs, chia was part of the basic foods in the civilizations of Central America, after corn and beans and before amaranth (De Meester & Watson, 2008). Tenochtitlan, the capital of the Aztec Empire, received between 5,000 and 15,000 tons of chia as an annual tribute from conquered nations (Codex Mendoza, 1542). Chia seed was not used just as a food, but was also offered to Aztec gods (Sahagún, 1579).

In was reported (Ayerza & Coates, 2001) that the oil content of chia seeds is 32-39% which provides the highest known percentage of α-linolenic acid extracted from a natural source since it represents 60% to 63% in the profile of fatty acids (FAs) in the oil. The oil contained in the chia has high oxidation stability, so the seed can be stored under environmental conditions without deterioration. Their stability is attributed to the antioxidants contain, specifically as polyphenols as quercetin, kaempferol, chlorogenic acid, and caffeic acid (Reyes et al., 2008, Vargas-Martínez & Beltrán-Orozco, 2011).

Traditionally in Mexico, chia seed is consumed in fresh water and several products have been added with these seeds, such as the study carried out by Morales (2007), in which a crowbar based on chia seed, amaranth and oats was elaborated for the population with a normal diet, as well as for people with a special diet. Currently, the United States Food and Drug Administration (FDA) considers chia a food, not a food additive, therefore exempts it for being regulated (Ricker, 2007). On the other hand, the European Food Safety Authority deems chia suitable for use in bread and cereal products (whole seeds and ground) and in the European Union the use of chia oil as an additive was authorized on December 8, 2014 (Besana Portalagrario, 2014), but it was considered a novel food ingredient (SINC Science News, 2013) since 2009.

Nowadays, experimental design is applied in many areas of science and in industrial applications (Ilzarbe et al., 2008, Muthukumar & Mohan, 2005, Deiab & Elbestawi, 2005, Schonning, 2005). In traditional experiments, only one factor is varied at a time, while all others remain constant. In multivariate designs, all the factors of interest can be investigated in a single trial, minimizing the number of experiments required and providing information on the key process interactions. In the areas of food analysis (Tonon et al., 2008, Tiwary et al., 2012, Jing et al., 2011), food processing and development (Wadikar et al., 2010, Dutcosky et al., 2006), as well as food sensory evaluation (Deshpande et al., 2008), many applications of the use of experimental design have been reported.

In the development of products added with chia seeds or flour, Luna (2013) reported the effects of adding whole chia flour on the technological, nutritional and sensory qualities of cakes based on a 22 central composite rotational design. Silveira-Coelho and Salas-Mellado (2015) using the same experimental design concluded that it was possible to reduce the levels of saturated fat and increase the levels of polyunsaturated fat (PUFA), mainly omega-3 FAs, including chia seeds or flour in breads, in addition to increasing the level of fiber, yielding products with the features of functional foods.

Key Terms in this Chapter

Variety: Means a plant grouping, within a single botanical taxon of the lowest known rank, defined by the reproducible expression of its distinguishing and other genetic characteristics.

Cultivar: Is a plant or group of plants that have been selected from a naturally occurring species and bred to enhance or maintain a particular set of desirable characteristics. These plants almost always originate from human cultivation, propagated through cutting or grafting, and often cannot be grown from seeds from the original plant.

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