Effect of Pulsed-Light Treatment on Milk Proteins and Lipids

• Published in: Journal of agricultural and food chemistry 2008-03, Vol.56 (6), p.1984-1991
• Main Authors: Elmnasser, Noura, Dalgalarrondo, Michèle, Orange, Nicole, Bakhrouf, Amina, Haertlé, Thomas, Federighi, Michel, Chobert, Jean-Marc
• Format: Article
• Language: English
• Subjects: amino acid composition; Amino Acids - analysis; analytical methods; Animals; Biological and medical sciences; Chemical Aspects of Biotechnology/Molecular Biology; chemical structure; composition; dairy products; Electrophoresis, Polyacrylamide Gel; Fats - analysis; food application; Food engineering; Food industries; food preservation; Food Preservation - methods; food processing; Fundamental and applied biological sciences. Psychology; lactoglobulins; Lactoglobulins - analysis; Life Sciences; Light - adverse effects; lipid peroxidation; Milk - chemistry; Milk - radiation effects; Milk and cheese industries. Ice creams; milk composition; milk fat; milk proteins; Milk Proteins - analysis; new methods; protein aggregates; protein conformation; Pulsed-light process; pulsed-light treatment; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; tryptophan
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf0729964

Pulsed-light treatment offers the food industry a new technology for food preservation. It allows the inactivation of numerous micro-organisms including most infectious foodborne pathogens. In addition to microbial destruction, one can also question whether pulsed-light treatment induced conformational changes in food components. To investigate this question, the influence of pulsed-light treatment on protein components of milk was evaluated by using UV spectroscopy, spectrofluorometry, electrophoresis, and determination of amino acid composition. Pulsed-light treatment resulted in an increase of UV absorbance at 280 nm. The intrinsic tryptophan fluorescence of β-lactoglobulin (BLG) showed a 7 nm red shift after 10 pulses. SDS-PAGE showed the formation of dimers after treatment of BLG by 5 pulses and more. No significant changes in the amino acid composition of proteins and lipid oxidation were observed after pulsed-light treatment. The obtained results indicated changes in the polarity of the tryptophanyl residue microenvironment of BLG solutions or changes in the tryptophan indole structure and some aggregation of studied proteins. Hence, pulsed-light treatment did not lead to very significant changes in protein components; consequently, it could be applied to process protein foods for their better preservation.