Comparison of cold-pressing and soxhlet extraction systems for bioactive compounds, antioxidant properties, polyphenols, fatty acids and tocopherols in eight nut oils

Antioxidant activities of different nut oils ranged from 11.43 (peanut) to 65.58% (pistachio) in cold pressed oils whereas in case of soxhlet extracted oils they were in the range of 11.32 (hazelnut) to 51.28% (pistachio). β-Carotene contents of oils obtained by cold pressing and soxhlet extraction changed between 7.53 (almond) and 13.58 µg/100 g (pistachio). The highest total phenol contents (2.36 mg gallic acid equivalent/100 g) were observed in pistachio oils obtained by cold press. The oleic acid contents of cold pressed and soxhlet extracted oils were between 19.88 (walnut) and 69.43% (pecan) to 19.07 (walnut) and 68.53% (pecan), respectively. The linoleic acid contents of nut oils from cold press system vary between 12.78 (hazelnut) and 63.56% (walnut), whereas in case of soxhlet extraction, it changed between 11.78 (hazelnut) and 62.41% (walnut). The α-tocopherol contents of cold pressed nut oils changed between 0.07 (walnut) and 257.42 mg/kg (hazelnut) α-tocopherol contents of nut oils extracted by soxhlet extraction changed between 0.03 (pistachio) and 209.73 mg/kg (hazelnut). The catechin contents of cold pressed nut oils were between 0.56 (cashew) and 3.76 µg/100 g (pistachio), whereas that of soxhlet extracted oil varied between 0.64 (cashew) and 3.82 µg/100 g (cashew).