Marcela L. Martínez

Variability in almond oil chemical traits from traditional cultivars and native genetic resources from Argentina

Almond (Prunus dulcis (Miller) D.A. Webb) genetic resources (Marcona, Guara, Non Pareil, IXL, AI, Martinelli C, Emilito INTA, Cáceres Clara Chica, Javier INTA) were studied during two consecutive crop years in order to evaluate variations in kernel oil yield and composition, and oil oxidative parameters. Total oil, oleic acid, α-tocopherol and squalene contents were found to range between 48.0% and 57.5%, 65% and 77.5%, 370 and 675 μg/g oil, and 37.9 and 114.2 μg/g oil, respectively. The genotype was the main variability source for all these chemical traits. The α-tocopherol content seems to be the most important contributor to both the radical scavenging capacity and the oxidative stability of almond oils analysed. Results obtained from the local genotypes namely Martinelli C, Emilito INTA and Javier INTA may be of interest for almond breeding focused to improve kernel oil yield and composition.

Matching Changes in Sensory Evaluation with Physical and Chemical Parameters

Changes in pistachio nuts induced by roasting and salting processes, evaluated by both sensory and instrumental analyses are reported, looking for a match in both methods. Dried (DP), roasted (RP), and salted–roasted pistachios (SRP) were studied, including four groups of sensory attributes, six basic chemical parameters, complemented by volatile organic compounds (VOCs) and breaking force. Multivariate statistics helped with data interpretation, enabling correlations between two groups of variables. Key results show that the perception of roasting is associated with increased amounts of α-pinene and 3-carene in RP and SRP, while DP are associated with higher amounts of limonene, moisture, and bitterness. Sensory and puncture test measurements (texturometer) showed opposite results, which could be explained considering the loss of plasticity in RP and SRP. Current results present a novel approach for the evaluation of changes in the perception of pistachio quality by consumers, supported by both sensory and instrumental analyses using multivariate statistics for data evaluation.

Extraction of bioactive compounds from sesame (Sesamum indicum L.) defatted seeds using water and ethanol under sub-critical conditions

Sesame seeds contain a vast array of lignans and phenolic compounds having important biological properties. An optimized method to obtain these seed components was designed by using water and ethanol at high pressure and temperature conditions. The maximum concentrations of lignans, total phenolics, flavonoids and flavonols compounds were achieved at 220°C extraction temperature and 8MPa pressure, using 63.5% ethanol as co-solvent. Under these conditions, the obtained sesame extracts gave the best radical scavenging capacity. Kinetic studies showed a high extraction rate of phenolic compounds until the first 50min of extraction, and it was in parallel with the highest scavenging capacity. The comparison of our results with those obtained under conventional extraction conditions (normal pressure, ambient temperature) suggests that recovery of sesame bioactive compounds may be markedly enhanced using water/ethanol mixtures at sub-critical conditions.

Effects on bread and oil quality after functionalization with microencapsulated chia oil: Effects on bread and oil quality after functionalization with microencapsulated chia oil

BACKGROUND Omega-3 and omega-6 fatty acids-rich oils suffer oxidation reactions that alter their chemical and organoleptic quality. Microencapsulation can be a powerful tool for protection against ambient conditions. In the present study, the addition of microencapsulated chia oil as an ingredient in bread preparations and its effect on the technological and chemical quality of breads was investigated. RESULTS Microencapsulation of chia oil was carried out by freeze-drying with soy proteins as wall material and oil release was determined under in vitro gastric and intestinal conditions. Encapsulated oil-containing bread showed no differences in specific volume, average cell area, firmness and chewiness with respect to control bread. Unencapsulated oil-containing bread showed a marked increase in hydroperoxide values respect to control, whereas encapsulated oil-containing bread values were not affected by baking and bread storage. The fatty acid profiles showed a decrease of 13% and 16%, respectively, in α-linolenic acid in the encapsulated and unencapsulated oils with respect to bulk chia oil. Sensory analysis showed no significant differences between bread samples. CONCLUSION The addition of encapsulated chia oil did not alter the technological quality of breads and prevented the formation of hydroperoxide radicals. A ration of encapsulated oil-containing bread contributes 60% of the recommended dietary intake of omega-3 fatty acids.

A Perspective on Production and Quality of Argentinian Nut Oils

Nuts are recommended constituents of the daily diet, although their real intake differs remarkably. Emerging proofs indicate that nuts may be a source of health promoting compounds that elicit cardioprotective effects. Nut fruits contain high levels of oil (50 – 70 %) and they are consumed fresh, toasted or salted, alone or in other edible products. Among the by-products of nuts industry, in general, the oil has not yet obtained popularity, although it has been demonstrated that its consumption has a lot of nutritional benefits. Their major constituents are triglycerides, in which unsaturated fatty acids are present in high amounts. The presence of other bioactive minor components, such as tocopherols and phytosterols, has been also documented.A major goal in nuts oils production is to find an appropriate method to recover oil from the seeds. To get high quality virgin oils, the process includes the selection of the fruits, the conditions of their transport and storage, the choice of the steps of the mechanical processing and finally the control of the storage and packaging conditions of the virgin oils. In recent years, there has been a resurgence of interest in the use of continuous, mechanical screw-presses to recover oil from oilseeds. Although screw pressing will not extensively replace solvent extraction in commodity oilseeds – because it recovers a lower proportion of oil; in the case of new specialty edible oils, screw pressing provides a simple and reliable method of processing small batches of seed. Moreover, mechanical pressing oil extraction is technically less extensive and less labor-intensive than the extraction solvent method. The safety and simplicity of the whole process is advantageous over the more efficient solvent extraction equipment. Furthermore, materials pressed out generally have better preserved native properties, end products are free of chemicals and it is a safer process.