Characterization and supercritical carbon dioxide extraction of walnut oil

Abstract

Walnut (Juglans regia L.) oil was extracted with compressed carbon dioxide (CO 2 ) in the temperature range of 308 to 321 K and in the pressure range of 18 to 23.4 MPa. The influence of particle size was also studied at a superficial velocity of 0.068 cm/s, within a tubular extractor of 0.2 L capacity (cross-sectional area of 16.4 cm 2 ). FFA, sterol, TAG, and tocopherol compositions were not different from those of oil obtained with n-hexane. The main FA was linoleic acid (56.5%), followed by oleic acid (21.2%) and linolenic acid (13.2%). The main TAG was LLL (linoleic, linoleic, linoleic) (24.4%), followed by OLL (oleic, linoleic, linoleic) (19.6%) and LLLn (linoleic, linoleic, linolenic) (18.4%). The main component of sterols was β-sitosterol (85.16%), followed by campesterol (5.06%). The amount of cholesterol was low (0.31 and 0.16% for oils extracted by n-hexane and supercritical fluid extraction, respectively. The CO 2 -extracted oil presented a larger amount of tocopherols (405.7 µg/g oil) when compared with 303.2 µg/g oil obtained with n-hexane. Oxidative stability determined by PV and the Rancimat method revealed that walnut oil was readily oxidized. Oil extracted by supercritical CO 2 was clearer than that extracted by n-hexane, showing some refining. A central composite, nonfactorial design was used to optimize the extraction conditions using the software Statistica, Version 5. The best results were found at 22 MPa, 308 K, and particle diameter (Dp) = 0.1 mm.Paper no. J9865 in JAOCS 79, 225-230 (March 2002).

Chemical composition, molecular weight distribution, secondary structure and effect of NaCl on functional properties of walnut (Juglans regia L) protein isolates and concentrates

“…The walnut kernel is of high food value with 65% oil and 18-24% protein contents, and it can be used as an adjunct in chocolate and chicken feeds, and also can be utilization as ingredient of many foodstuffs such as bakery products to enhance the nutrition value of products (Mexis et al 2009). Walnuts oil is major product of walnut production and is one of the important special oils used for salad dressing and cooking (Oliveira et al 2002). Besides walnut oil and protein, Walnut contain 12~16% carbohydrates, 1.5~2.0% cellulose, 1.7~2.0% mineral (Lavedrine et al 2000;Prasad 2003;Savage 2001;Sze-Tao and Sathe 2000b;Wardlaw 1999;Gharibzahedi et al 2011).…”

Analysis of the headspace aroma compounds of walnuts (Juglans regia L.)

“…3 Several authors have published values for the lipid content of walnut kernels, [2][3][4][5][6][7] as well as the lipid composition of walnut oil. 2,[4][5][6][7][8][9] In these publications, values for the lipid content of walnut kernels are in the range 62-70%. The two main PUFAs are linoleic acid, which comprises 49-72% of the total fatty acids, and α-linolenic acid, which comprises 8-25% of the total fatty acids.…”

Supercritical extraction of evening primrose oil: Experimental optimization via response surface methodology

“…15,16 RSM is a faster and more economical method for gathering research results than classic one-variable-at-a-time or full-factors experimentation. RSM has been successfully used to model and optimize supercritical CO 2 extraction of oils from grape seed, 13 cherry seed, 17 walnut, 18 apricot kernel, 19 hazelnut, 20 rosemary, 21 and rosehip seed. 22 In this study, the SC-CO 2 was used to extract the oil from the evening primrose seeds.…”