Presence of Testa and Shell Maintains Oil Stability in Almond and Canarium Nuts

(1) Background: The oil stability of tree nuts during storage can be influenced by storage conditions such as temperature, humidity, and moisture concentration. However, few studies have assessed how the presence of testa and shell affects the oil stability of tree nuts during storage. We aimed to determine how storage conditions affect oil stability in almond and canarium, in particular, the presence of testa and storage time of nut-in-shell (NIS). (2) Methods: We measured peroxide value (PV), free fatty acid (FFA) and hexanal concentrations of almond and canarium (blanched vs. kernel-in-testa) stored at 45 °C for 24 days. We also measured PV, FFA and fatty acid composition of canarium samples at days 0 and 140 stored as NIS under ambient conditions. (3) Results: The presence of testa in almond and canarium decreased hexanal and PV concentrations at day 24 of incubation. Canarium PV and FFA concentrations increased over 140 days of storage in the shell compared to day 0. However, both PV and FFA concentrations remained within the acceptable threshold during storage. No changes in fatty acid composition were found during NIS storage. (4) Conclusions: Testa and shell could act as a natural coating, slowing down oxidation rates. Hence, long-term storage on nuts in testa or nuts in shell are recommended for tree nuts

Organic Matter Fractions Controlling Soil Water Repellency in Sandy Soils From the Doñana National Park (Southwestern Spain)

11 páginas.-- 5 figuras.-- 3 tablas.-- 102 referencias.-- Special Issue: Advances Towards an Integrated Assessment of Fire Effects on Soils, Vegetation and Geomorphological ProcessesThe relationship between soil organic matter (SOM) content and organic molecular assemblages (n-alkane/alkenes pairs and n-fatty acids) with soil water repellency (WR) in different sieve fractions (1–2, 0·25–1, 0·05–0·5 and  PA > PP > HH. A positive correlation was found between soil WR from each sieve fraction and SOM content. Most severe soil WR was detected in QS for all sieve fractions, followed by the finer fractions ( PA > HH. A significant correlation was observed between SOM content and the severity of soil WR in QS samples and finer fractions of soil under other vegetation (PA, PP and HH). Coarser fractions (1–2 mm) from PP, PA and HH 1–2 mm sieve fractions showed high severity of WR and relatively low SOM contents that could be explained by a low degree of evolution of the organic residues as seen by analytical pyrolysis, that is, higher alkane/alkene carbon preference index values and the presence of a higher diversity of fatty acid structures. CopyrightThis work has been partly funded by the Spanish Ministry for Economy and Competitiveness through projects HYDFIRE (CGL2010-21670-C02-01) and GEOFIRE (CGL2012-268 38655-C04-01). The firstauthor has been granted by a fellowship for Formation of Research Staff (BES-2013-062573) by the Spanish Ministry for Economy and Competitiveness.Peer reviewe

Fatty acid composition (percentages) of <i>Canarium indicum</i> under different roasting regimes.

<p>Paired bold cases represent a significant difference at P<0.05.</p

Effects of roasting on kernel peroxide value, free fatty acid, fatty acid composition and crude protein content - Fig 2

<p>Peroxide values (A) and free fatty acid (FFA) (B) of the roasted <i>Canarium indicum</i> kernels at 110°C, 120°C and 150°C temperatures for 5 min (hatched column), 10 min (grey column) and 20 min (black column) compared to raw kernel (white column). FFA of the testa-off and testa-on kernels at 110°C (white and black columns, respectively) and at 120°C (grey and hatched columns, respectively) (C). Different lower case letters indicate significant differences at P<0.05.</p

<i>Canarium indicum</i> kernels (%) in each colour category and mottled colour category for different roasting regimes.

<p><i>Canarium indicum</i> kernels (%) in each colour category and mottled colour category for different roasting regimes.</p

<i>Canarium indicum</i>—Nut and removed pulp (A), testa-on kernels (B) and testa-off kernels (C).

<p><i>Canarium indicum</i>—Nut and removed pulp (A), testa-on kernels (B) and testa-off kernels (C).</p

Probability of two-way ANOVA for oil volume, moisture content, peroxide value (PV), free fatty acid (FFA), fatty acid composition, total saturated fatty acid (TSFA), total unsaturated fatty acid (TUSFA), oleic:linoleic ratio and protein content of <i>Canarium indicum</i> after roasting.

<p>Probability of two-way ANOVA for oil volume, moisture content, peroxide value (PV), free fatty acid (FFA), fatty acid composition, total saturated fatty acid (TSFA), total unsaturated fatty acid (TUSFA), oleic:linoleic ratio and protein content of <i>Canarium indicum</i> after roasting.</p