Characterization of Almond Cultivars by the Use of Thermal Analysis Techniques. Application to Cultivar Authenticity

Abstract

Almonds are subjected to thermal processes in the production of processed food and this can affect their thermal stability and lead to oxidation processes. In this work, almond samples from three different cultivars (Spanish Guara and Marcona, and American Butte) were characterized by using Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) at different heating rates. Crystallization and melting parameters were determined by DSC; whereas thermal stability was studied by TGA, showing no apparent degradation for all samples up to around 290°C. Butte samples showed the lowest DSC values and TGA initial degradation temperature. These results were linked with differences in fatty acid profiles between Butte and Spanish almond cultivars, Butte presenting higher linoleic acid content. Successful discrimination was obtained for samples analyzed at 2 and 10°C min -1 heating rates for DSC and TGA, respectively, by applying multivariate stepwise linear discriminant analysis (LDA). The results obtained proved the suitability of thermal analysis techniques combined with LDA for an easy and fast discrimination among different almond cultivars to control eventual adulteration in food processing.

Application of a multidisciplinary approach for the evaluation of traceability of extra virgin olive oil

“…Good resolution among categories was achieved in all cases as shown by the low λ w values obtained. In particular, the application of DSC and related thermal properties, which was a novelty in the field of olive oil but was very recently and successfully utilized to discriminate food samples of different botanical origin 31, may be suitable for this purpose in combination with other techniques. Among thermal properties, those obtained from the deconvoluted peaks of transition (in particular peak 3 at the highest temperature of cooling transition) were more discriminant than those obtained by analysing the whole cooling profiles, confirming hypotheses from previous studies by the same authors 22.…”

Effect of Frying and Roasting Processes on the Oxidative Stability of Sunflower Seeds (Helianthus annuus) under Normal and Accelerated Storage Conditions

“…In general, AV tended to increase at 100 • C showing the formation of secondary oxidation products in accordance with the obtained PV values. Similar results were obtained in previous works with other nuts such as Spanish and American almond oils [27].…”

“…Sunflower seed samples were directly analyzed by ATR-FTIR, HS-SPME-GC-MS, DSC, and TGA. For fatty acid composition and PV and AV determinations, the oil of samples was extracted by applying an analytical method previously developed [27]. Triplicates were carried out for all the analyses.…”

Kinetic Study of Olive Oil Degradation Monitored by Fourier Transform Infrared Spectrometry. Application to Oil Characterization

“…Nevertheless, this subject has received little attention, and very few studies can be found in the literature in which kinetic data are used to compare oxidative behaviors of different sorts of oils. In some of these studies isothermal differential scanning calorimetry data 19 and the Rancimat test have been used to characterize different vegetable oils. 20,21 In recent years, the number of virgin oils from different olive cultivars has grown enormously in supermarkets trying to highlight the better quality of olive oils from nutritional and culinary points of view.…”

“…Nevertheless, this subject has received little attention, and very few studies can be found in the literature in which kinetic data are used to compare oxidative behaviors of different sorts of oils. In some of these studies isothermal differential scanning calorimetry data and the Rancimat test have been used to characterize different vegetable oils. , …”