Christianne E.C. Rodrigues

Deacidification of Vegetable Oils by Solvent Extraction

The refining of edible oils requires a series of purification steps, with the most important being the decrease of the free fatty acid level of the crude oil. This step is very important for the quality of the final product and has a major impact on the economic feasibility of the whole process. Several techniques, alternative to the conventional caustic or steam distillation methods, are suggested in the literature, such as supercritical extraction, membrane technology and solvent extraction. In the present paper we discuss the main aspects related to the solvent extraction technique, coupled or not with the conventional methods. The reviewed patents indicate various advantages of a purification process based on the selective extraction of free fatty acids using short chain alcohols. Its technical feasibility is due to the differences in solubility of free fatty acids and neutral oil in the proposed solvents. This alternative technique does not generate waste products and can preserve nutraceutical compounds in the refined oil.

Storage of refrigerated raw goat milk affecting the quality of whole milk powder.

The aim of this study was to evaluate the influence of the growth of lipolytic bacteria in raw goat milk stored under refrigeration for different periods on quality parameters of goat milk powder during its shelf life. Fresh goat milk (100L) was collected after milking, divided into 3 identical fractions, and stored at 4°C for 1, 3, and 5d. On d 1, 3, and 5, one sample (1L) was collected and used for microbiological and chemical analysis, and the remaining fraction (almost 30L) was spray dried and stored at 25°C. Milk powder was submitted to microbiological, chemical, and sensory analysis immediately after production, and on d 60, 120, and 180. Lipolytic psychrotrophic counts and total free fatty acid content did not increase in raw milk during storage. However, peroxide value, caprylic and capric acid concentrations, and total free fatty acid content of milk powder increased during 180d of storage, with higher levels found in milk powder manufactured with raw milk stored for 5d. Capric odor and rancid flavors increased in milk powder during storage, regardless the of storage of raw milk for 1, 3, or 5d. Heat treatments used during powder processing destroyed lipolytic psychrotrophic bacteria, but did not prevent lipolysis in milk powder. Results of this trial indicate that the storage of raw goat milk at 4°C should not exceed 3d to preserve the quality of goat milk powder during its shelf life of 180d.

Peanut skin extract reduces lipid oxidation in cooked chicken patties

The objectives of this study were to evaluate the antioxidant capacity of peanut skin extract and its effect on the color and lipid oxidation of cooked chicken patties over 15 d of refrigerated storage. The extract was obtained using 80% ethanol and evaluated in terms of total phenolic content, reducing power based on the ferric reducing ability of plasma (FRAP) reagent, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. The patties were made with ground thigh fillets, chicken skin, and 2% salt. They were homogenized and divided into the following two groups: a control treatment without antioxidants and a peanut skin treatment with 70 mg gallic acid equivalent (GAE)/kg per patty. Analyses of the fatty acid profiles, instrumental colors (L*, a*, and b*) and thiobarbituric acid reactive substances (TBARS) were performed on d 1, 8, and 15 of storage at 1±1ºC. The peanut skin extract resulted in a phenolic content of 32.6±0.7 mg GAE/g dry skin, an antioxidant activity (FRAP) of 26.5±0.8 6 μmol Trolox equivalent/g dry skin, and an efficient concentration (EC50) of 46.5 μg/mL. The total unsaturated fatty acid was approximately 73%, and 39% of this fatty acid content was monounsaturated. The peanut skin extract slowed the decrease in the a* values (P<0.05) but reduced the L* and b* values compared to the control samples during storage (P<0.05). Lipid oxidation was minimized by the peanut skin extract (P<0.05), which resulted in a maximum value of 0.97 malondialdehyde (MDA)/kg compared to values that were close 19 mg MDA/kg patties in the control sample at the end of storage period. Thus, it can be concluded that although peanut skin extract causes little color change, it can be applied as a natural antioxidant to cooked chicken patties because it efficiently inhibits lipid oxidation in this product during refrigerated storage.

Incidence of Aflatoxins in Oil Seeds and Possible Transfer to Oil: A Review

Aflatoxins are secondary metabolites produced by fungi of the genus Aspergillus, predominantly by A. flavus,A. parasiticus and A. nomius, which occur naturally in foodstuffs, leading to a wide variety of toxic effects in vertebrates, including humans. Contamination of food products with aflatoxigenic fungi may occur during production, harvesting, processing, transportation and storage. Human exposure to mycotoxins occurs primarily through the ingestion of contaminated food, including corn, peanuts, cotton seeds, as well as other oily seeds, such as sunflower and coconut. The procedures used for the extraction and refining of edible vegetable oils can be effective in reducing aflatoxins, varying with the type of oil and method of oil refining. However, numerous studies have reported high incidence of aflatoxins contamination in edible oils worldwide. The production of oils from oilseeds requires the following steps: storage of grains, preparation, extraction of crude oil and refine (degumming, deacidification, bleaching, deodorization, among others). Some of these steps may be harsh and lead to inactivation or elimination of important compounds, such as vitamins, antioxidants and enzymes, although the effect on undesirable compounds like aflatoxins varies markedly among methods. This review presents the current data on the contamination of aflatoxigenic fungi and incidence of aflatoxins in raw oilseed as well as derived products, the main technological approaches for the oil production, and discusses the potential transfer of aflatoxins from oilseeds into the final oil product through the process.

Experimental data and modeling of rice bran oil extraction kinetics using ethanol as solvent

ABSTRACT The extraction kinetics of rice bran oil (RBO), free fatty acids (FFA), and oryzanol using ethanol (0 and 6.3 mass % of water) at 40°C–70°C were investigated. High extraction temperatures increased the yields of RBO and oryzanol by increasing the diffusivity of the solvent, regardless of its water content. Two models that permitted the estimation of mass transfer and diffusion coefficients were fitted to the oil extraction data with low average relative deviations (≤5.92%). The diffusion coefficient (1.93–7.46 × 10–10 m2∙s–1) increased with increasing temperature and decreasing hydration of the solvent.

Effect of the type and level of hydration of alcoholic solvents on the simultaneous extraction of oil and chlorogenic acids from sunflower seed press cake

BACKGROUND The present study aimed to evaluate the replacement of hexane by alcoholic solvents in oil extraction from sunflower seed press cake. The use of ethanol and isopropanol has important advantages, including low toxicity and good operational safety. Thus, in the present study, solid-liquid extractions were performed in a single stage from 60 to 90 °C and in consecutive extractions in three stages at 90 °C. RESULTS Solvent hydration negatively affected the extraction of oil but favored the extraction of chlorogenic acids (CAs), especially when ethanol was used. Regarding oxidative stability, the oils extracted using ethanol presented long induction times, which could be related to the high levels of not only CAs and tocopherols, but also phospholipids. CONCLUSION Alcoholic solvents can be used for extraction to produce sunflower seed oil containing minor compounds that give it greater oxidative stability. In addition, the results obtained using hydrous ethanol showed that this solvent can yield defatted sunflower seed meal with a low content of CAs, enabling future use of the protein fraction.

Pressurized liquid extraction of flavanols and alkaloids from cocoa bean shell using ethanol as solvent

Cocoa shell (CS) is a co-product of the cocoa industry used mainly as fuel for boilers but with secondary applications as fertilizer and in animal feed. Although it is known that this material is rich in flavanols and alkaloids, to date, a study has not been conducted that has quantitatively identified these compounds in CS. Thus, the aim of this work was to characterize CS in terms of its composition, regarding catechin, epicatechin, procyanidin B2, caffeine and theobromine, and to evaluate the extraction kinetics of the total flavanols using pressurized liquid extraction (PLE) with absolute ethanol. For the determination of the extraction kinetic data, the DMAC method was used, while each compound was quantified using a UPLC-MS/MS analysis. The major compounds found were theobromine and epicatechin (mean values of 9.89 and 3.5 mg/g CS, respectively). PLE proved to be quite effective; the flavanols extraction yield was enhanced by increasing the temperature and extraction time however, high extraction times and temperatures degraded the procyanidins B2. Pelegs model applied to extraction data description provided a reasonable agreement with the experimental results, which allows their application in modeling and optimization of solid-liquid extraction of the total flavanols from cocoa bean shell.

Extração de oleuropeína a partir de folhas de oliveira utilizando solvente hidroalcoólico

Olive leaves contain oleuropein, a substance known for its antioxidant, antimicrobial and antiinflammatory potentials, amongst others. The objective of this work was to study the extraction of oleuropein using a hydroalcoholic solvent. Olive leaves (OL) were macerated at 25 °C with a solvent (S) consisting of a mixture of ethanol and water (70:30 v/v), with OL:S mass ratios equal to 1:8, 1:6 and 1:3, with or without the presence of acetic acid. The highest oleuropein content found in the freeze dried extract (approximately 18 g/100 g) was obtained from the procedure using an OL:S ratio = 1: 3, in the presence of acetic acid. Finally, a test was carried out to verify the effect of the freeze dried extract on the induction time in samples of extra-virgin and refined olive oil, and increases of 3 and 2 hours, respectively, were observed. It was concluded that it is possible to obtain olive leaf extracts using renewable solvents, and that oleuropein can act as a natural antioxidant in olive oil, improving its oxidative stability.