Oxidation in Low Moisture Foods as a Function of Surface Lipids and Fat Content

Lipid oxidation is a major limitation to the shelf-life of low moisture foods and can lead to food waste. Little is known of whether the surface lipids in low moisture foods are more susceptible to oxidation since they are exposed to the environment. Therefore, the purpose of this research is to compare the rate of oxidation in surface and total lipids. Lipids in crackers were found to be in a heterogeneous matrix with proteins and starch, as determined by confocal microscopy. However, unlike spray-dried powders, both surface and interior lipids oxidized at similar rates, suggesting that the cracker matrix was not able to protect lipids from oxidation. Increasing the fat content of the crackers increased oxidation rates, which could be due to differences in the lipid structure or higher water activities in the high-fat crackers

Estabilidad oxidativa de mezclas de aceites de palma y piel de avellana con alto contenido oleico

8 páginasHigh oleic palm oil (HOPO) with high oleic and palmitic acid contents is a new vegetable oil that needs to find further use in food applications, while hazelnut skin oil (HSO) with high oleic acid content is a by-product of hazelnut oil production and have no commercial value. The aim of the study was to obtain new oil blends for new food formulations with high oxidative stability and low (or reasonable) saturated fatty acid content using HOPO and HSO. For this aim, they were blended in the proportions of 0 to 100% (wt/wt), and fatty acid and tocol compositions, induction period and storage stability of the blends were evaluated. Tocotrienols (560.94 mg/kg) constitute the majority of the tocol content of HOPO, while tocopherols (437.69 mg/kg) were the major tocols of HSO. HOPO has a higher saturated fatty acid composition and lower monounsaturated fatty acids content than HSO. In general, it was determined that increasing the HSO ratio in oil blends reduced their oxidative stabilities, which is most likely because HSO is richer in total unsaturated fatty acids (91.8%) than HOPO (68.4%). In addition, tocotrienols are known to be stronger antioxidants than tocopherols. Although HOPO is rich in γ-tocotrienol, which has a strong antioxidant activity, it also has some disadvantages such as having a high price and containing significant levels of saturated fatty acids (mainly palmitic acid). The optimum blend ratio was then determined as 50% HOPO:50% HSO considering oxidative stability and fatty acid compositions.El aceite de palma alto en oleico (HOPO) con alto contenido de ácido oleico y palmítico es un nuevo aceite vegetal que necesita encontrar un mayor uso en aplicaciones alimentarias, mientras que el aceite de piel de avellana (HSO) con alto contenido de ácido oleico es un subproducto de la producción de aceite de avellana. y no tienen valor comercial. El objetivo del estudio fue obtener nuevas mezclas de aceites para nuevas formulaciones alimentarias con alta estabilidad oxidativa y bajo (o razonable) contenido de ácidos grasos saturados utilizando HOPO y HSO. Para este objetivo, se mezclaron en proporciones de 0 a 100% (peso/peso) y se evaluaron las composiciones de ácidos grasos y tocoles, el período de inducción y la estabilidad de almacenamiento de las mezclas. Los tocotrienoles (560,94 mg/kg) constituyen la mayor parte del contenido de tocoles de HOPO, mientras que los tocoferoles (437,69 mg/kg) fueron los principales tocoles de HSO. HOPO tiene una mayor composición de ácidos grasos saturados y un menor contenido de ácidos grasos monoinsaturados que el HSO. En general, se determinó que el aumento de la proporción de HSO en las mezclas de aceites reducía su estabilidad oxidativa, lo que probablemente se debe a que el HSO es más rico en ácidos grasos insaturados totales (91,8%) que el HOPO (68,4%). Además, se sabe que los tocotrienoles son antioxidantes más fuertes que los tocoferoles. Aunque el HOPO es rico en γ-tocotrienol, que tiene una fuerte actividad antioxidante, también tiene algunas desventajas como tener un precio elevado y contener niveles importantes de ácidos grasos saturados (principalmente ácido palmítico). Luego se determinó que la proporción de mezcla óptima era 50% HOPO:50% HSO considerando la estabilidad oxidativa y las composiciones de ácidos grasos

Role of Solid Fat Content in Oxidative Stability of Low-Moisture Cracker Systems

Lipid oxidation is a major pathway for the chemical deterioration of low-moisture foods. Little is known about how the physical properties of the fat used in crackers impact lipid oxidation kinetics. Fully hydrogenated soybean fat + interesterified soybean oil, fully hydrogenated soybean fat + sunflower oil, fully hydrogenated soybean oil, and soybean oil and interesterified fat alone were formulated to have varying solid fat content (SFC) at 55 °C but the same linoleic acid and tocopherol contents, so the fats had similar susceptibility to oxidation. A fluorescence probe showed that lipid mobility increased with decreasing SFC in both cracker doughs and fat blends, suggesting the probe could be used to monitor SFC directly in foods. Decreasing SFC decreased oxidation in crackers. Crackers made from interesterified fat (13.7% SFC) were more oxidatively stable (hexanal lag phase = 33 days) than crackers made from fat blends (hexanal lag phase = 24 days). These results suggest that blended fats result in regions of liquid oil high in unsaturated fatty acids within a food product prone to oxidation. Conversely, interesterified fats where unsaturated and saturated fatty acids are more evenly distributed on the triacylglycerols are more stable. Thus, interesterified fats could allow for the formulation of products higher in unsaturated fatty acids to improve nutritional profiles without sacrificing shelf life