title: Fatty acids characterization, oxidative perspectives and consumer acceptability of oil extracted from pre-treated chia (Salvia hispanica L.) seeds.
abstract: BACKGROUND
  Chia (Salvia hispanica L.) seeds have been described as a good source of lipids, protein, dietary fiber, polyphenolic compounds and omega-3 polyunsaturated fatty acids. The consumption of chia seed oil helps to improve biological markers related to metabolic syndrome diseases. The oil yield and fatty acids composition of chia oil is affected by several factors such as pre-treatment method and size reduction practices. Therefore, the main mandate of present investigate was to study the effect of different seed pre-treatments on yield, fatty acids composition and sensory acceptability of chia oil at different storage intervals and conditions.
  
  
  METHODS
  Raw chia seeds were characterized for proximate composition. Raw chia seeds after milling were passed through sieves to obtain different particle size fractions (coarse, seed particle size ≥ 10 mm; medium, seed particle size ≥ 5 mm; fine, seed particle size ≤ 5 mm). Heat pre-treatment of chia seeds included the water boiling (100 C°, 5 min), microwave roasting (900 W, 2450 MHz, 2.5 min), oven drying (105 ± 5 °C, 1 h) and autoclaving (121 °C, 15 lbs, 15 min) process. Extracted oil from pre-treated chia seeds were stored in Tin cans at 25 ± 2 °C and 4 ± 1 °C for 60-days and examined for physical (color, melting point, refractive index), oxidative (iodine value, peroxide value, free fatty acids), fatty acids (palmitic, stearic, oleic, linoleic, α-linolenic) composition and sensory (appearance, flavor, overall acceptability) parameters, respectively.
  
  
  RESULTS
  The proximal composition of chia seeds consisted of 6.16 ± 0.24 % moisture, 34.84 ± 0.62 % oil, 18.21 ± 0.45 % protein, 4.16 ± 0.37 % ash, 23.12 ± 0.29 % fiber, and 14.18 ± 0.23 % nitrogen contents. The oil yield as a result of seed pre-treatments was found in the range of 3.43 ± 0.22 % (water boiled samples) to 32.18 ± 0.34 % (autoclaved samples). The oil samples at day 0 indicated the maximum color (R and Y Lovibond scale) value for oven drying while at storage day 60 (25 ± 2 °C), the highest color value was found for autoclave pre-treatment. The slightly increasing trend of color values for all treatments was observed during the storage period. The lowest iodine value (182.83 ± 1.18 g/100 g at storage day 0 & 173.49 ± 1.21 g/100 g at storage day 60, 25 ± 2 °C) was calculated for autoclaved samples while the maximum iodine value (193.42 ± 1.14 g/100 g at storage day 0 & 190.36 ± 1.17 g/100 g at storage day 60, 25 ± 2 °C) was recorded for raw chia samples. The significant increasing trend for all treatments was observed in case of peroxide value and free fatty acids production during storage. Maximum decrease in linoleic (35 %) and α-linolenic (18 %) fatty acids was observed in autoclaved samples. The oil from pre-treated seed samples obtained decreasing scores for sensory parameters throughout the storage period at different conditions.
  
  
  CONCLUSIONS
  As a result, chia seeds are an important source of lipids and essential fatty acids. The water boiling and high temperature processing of chia seeds provides instability to lipids during storage at room temperature. However, detailed investigation is required on the processing performance and storage stability of food products supplemented with pre-treated chia seeds and furthers their effect on biological system.
authors.affiliation: Institute of Home and Food Sciences, Faculty of Science and Technology, Government College University, Faisalabad, Pakistan. imran@gcuf.edu.pk.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Imran
authors.affiliation: Department of Dairy Technology, University of Veterinary and Animal Sciences, Lahore, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Nadeem
authors.affiliation: Department of Food Science, Nutrition and Home Economics, Government College University, Faisalabad, Pakistan.
authors.forename: Muhammad Faisal
authors.initials: MF
authors.lastname: Manzoor
authors.affiliation: Department of Food Science, Nutrition and Home Economics, Government College University, Faisalabad, Pakistan.
authors.forename: Amna
authors.initials: A
authors.lastname: Javed
authors.affiliation: Department of Food Science, Nutrition and Home Economics, Government College University, Faisalabad, Pakistan.
authors.forename: Zafar
authors.initials: Z
authors.lastname: Ali
authors.affiliation: Department of Food Science and Nutrition, Government College University, Sub Campus Layyah, Pakistan.
authors.forename: Muhammad Nadeem
authors.initials: MN
authors.lastname: Akhtar
authors.affiliation: Department of Food Science, Nutrition and Home Economics, Government College University, Faisalabad, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Ali
authors.affiliation: Department of Food Science, Nutrition and Home Economics, Government College University, Faisalabad, Pakistan.
authors.forename: Yasir
authors.initials: Y
authors.lastname: Hussain
mesh_terms: D004043:Dietary Fiber / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000737:chemistry* / Q000378:metabolism; D006358:Hot Temperature; D008055:Lipids / Q000737:chemistry*; D010084:Oxidation-Reduction; D010938:Plant Oils / Q000737:chemistry* / Q000378:metabolism; D027544:Salvia / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D004043:Dietary Fiber; D015525:Fatty Acids, Omega-3; D008055:Lipids; D010938:Plant Oils; D014867:Water
keywords: Lipid profile; Oxidation; Physical parameters; Salvia hispanica; Size reduction; Storage; Thermal processing