Article pubs.acs.org/JAFC
Influence of Ultra-high-Pressure Homogenization Treatment on the Phytosterols, Tocopherols, and Polyamines of Almond Beverage Natalia Toro-Funes, Joan Bosch-Fusté, M. Teresa Veciana-Nogués, and M. Carmen Vidal-Carou* Department of Nutrition and Food Science-XaRTA, INSA, Campus de l’Alimentació de Torribera, University of Barcelona, Avinguda Prat de la Riba 171, 08921 Santa Coloma de Gramenet, Barcelona, Spain ABSTRACT: Ultra-high-pressure homogenization (UHPH) is an emerging technology based on the dynamic application of high pressure to obtain safe and high-quality liquid foods. The effect of six UHPH treatments at 200 and 300 MPa with different inlet temperatures (Tin) (55, 65, and 75 °C) on the content of tocopherols, polyamines, and phytosterols of almond beverage was studied in comparison with the base product. Total tocopherol contents decreased about 80−90% as temperature and pressure increased, and whereas both parameters affected the tocopherol content, especially the effect of temperature was noticeable. αTocopherol was the most predominant type of tocopherol present and was also the most affected by UHPH treatments. Spermidine was the only polyamine found not to be affected by UHPH treatments. UHPH treatments resulted in an increase of 20−40% in the total phytosterol extractability. The highest extractability was obtained at the most severe conditions (300 MPa, 75 °C Tin). KEYWORDS: almonds, almond milk, UHPH, bioactive compounds, antioxidants, emerging technologies
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INTRODUCTION Almonds (Prunus dulcis) are the most important tree nut product worldwide. They are an important and valuable specialty crop grown mainly in a Mediterranean climate. Almonds may play an important role in the daily human intake of bioactive phytocompounds, and also they are an important source of nutrients.1 Studies on the health benefits of daily nut consumption, especially in relation to blood lipids, cardioprotective effects, and metabolic health, have been extensively reviewed.2−4 The consumption of almonds has been associated with the total and low-density lipoprotein (LDL) cholesterollowering effects and prevention of cardiovascular diseases.5 The beneficial health effects of almonds are attributed to the fatty acid profile, rich in monounsaturated fatty acids, and the socalled phytochemical components such as antioxidant compounds and phytosterols.6−8 Almonds have been incorporated in the Mediterranean diet for thousands of years, during which almonds have been used extensively in traditional recipes. Almond beverage has usually been consumed in the Mediterranean area as a substitute of cow’s milk for lactose-intolerant and allergic to milk proteins individuals or for those who avoid milk for other reasons. Commercial almond milk is conventionally processed by heat treatments, especially ultra-high temperature (UHT), which are useful and necessary to improve palatability and digestibility. However, such a combination of temperature and time of heating may cause undesirable modifications and destruction of some nutritive compounds. Almond beverage is a complex dispersion formed by oil droplets and proteins that requires a homogenization step to obtain a high degree of stability during its commercial shelf life. Homogenization is needed to reduce the size of fat globules and other disperse particles to prevent creaming and coalescence during storage, to produce fine and stable emulsions, and to improve protein-stabilizing properties.9,10 © 2014 American Chemical Society
The use of ultra-high-pressure homogenization (UHPH) allows achieving these effects to obtain safe and high-quality liquid foods.11 UHPH is based on the same principle as conventional homogenization, but it works at significantly higher pressures (up to 400 MPa). In recent years, an increase of stability in vegetable beverage emulsions, such as soy milk and almond beverage, has been demonstrated.12,13 In a previous work, we reported that selected UHPH conditions allowed an improvement of the extractability of potentially health-related compounds in soy milk, such as phytosterols from the fat globules or isoflavones from proteins.14 However, the effects of nonconventional technologies differ not only according to treatment intensity but also according to food matrix, suggesting that each matrix should be studied separately.15 Therefore, the aim of this work is to assess the effect of UHPH on the health-related bioactive compounds phytosterols, tocopherols, and polyamines in almond beverage. To our knowledge, there are no previous studies evaluating the effect of UHPH upon the bioactive compounds in almond products.
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MATERIALS AND METHODS
Sample Treatments. Almond Beverage Elaboration. Almond beverage samples were produced in the pilot plant of the Autonomous University of Barcelona (Centre Especial de Recerca Planta de Tecnologia dels Aliments (CERPTA)). The elaboration process and the technological conditions applied for their production are described in the work reported by Valencia-Flores et al.13 Three productions of almond beverage were performed. All productions were elaborated from the same raw material (12 kg of almonds). For each production, 4 kg of ground almonds (P. dulcis var. Marcona) were hydrated in 100 L with heat control at 60 °C Received: Revised: Accepted: Published: 9539
April 29, 2014 September 4, 2014 September 4, 2014 September 4, 2014 dx.doi.org/10.1021/jf503324f | J. Agric. Food Chem. 2014, 62, 9539−9543
Journal of Agricultural and Food Chemistry
Article
Table 1. Mean (Standard Deviation) Total Tocopherols in Base Product and UHPH-Treated Almond Beverage Samplesa α-tocopherol (mg/L) base product 200 MPa, 55 200 MPa, 65 200 MPa, 75 300 MPa, 55 300 MPa, 65 300 MPa, 75
°C °C °C °C °C °C
Tin Tin Tin Tin Tin Tin
46.60 7.92 7.06 4.14 7.14 5.98 3.15
γ-tocopherol (mg/L)
δ-tocopherol (mg/L)
1.47 (0.30) 1.58 (0.25) 0.99 (0.06)
