Browsing by Author "Sasaki, Keisuke"

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Differentiation of Animal Fats from Different Origins: Use of Polymorphic Features Detected by Raman Spectroscopy
(2010-11-01)
Motoyama, Michiyo
;
Ando, Masahiro
;
Sasaki, Keisuke
;
Hamaguchi, Hiro-O
;
應用化學系
Food safety requires the development of reliable techniques that ensure the origin of animal fats. In the present work, we try to verify the efficacy of using the polymorphic features of fats for discriminating animal-fat origins. We use Raman spectroscopy to collect the structural information of fat crystals. It is shown that a single Raman band at 1417 cm(-1) successfully differentiates pork fats from beef fats. This band is known to be characteristic of the beta'-polymorph of fats. Pork fats show this band because they contain the beta'-polymorph after rapid cooling to 0 degrees C. In beef pork-fat mixtures, this hand is not detected even in the presence of 50% pork fat; an addition of beef fat to pork fat is likely to produce a mixed fat with a completely different polymorphic behavior. This method seems to have the potential to detect beef products contaminated with pork-adipose tissue.
Simultaneous imaging of fat crystallinity and crystal polymorphic types by Raman microspectroscopy
(2016-04-01)
Motoyama, Michiyo
;
Ando, Masahiro
;
Sasaki, Keisuke
;
Nakajima, Ikuyo
;
Chikuni, Koichi
The crystalline states of fats, i.e., the crystallinity and crystal polymorphic types, strongly influence their physical properties in fat-based foods. Imaging of fat crystalline states has thus been a subject of abiding interest, but conventional techniques cannot image crystallinity and polymorphic types all at once. This article demonstrates a new technique using Raman microspectroscopy for simultaneously imaging the crystallinity and polymorphic types of fats. The crystallinity and beta\' crystal polymorph, which contribute to the hardness of fat-based food products, were quantitatively visualized in a model fat (porcine adipose tissue) by analyzing several key Raman bands. The emergence of the beta crystal polymorph, which generally results in food product deterioration, was successfully imaged by analyzing the whole fingerprint regions of Raman spectra using multivariate curve resolution alternating least squares analysis. The results demonstrate that the crystalline states of fats can be nondestructively visualized and analyzed at the molecular level, in situ, without laborious sample pretreatments. (C) 2015 Elsevier Ltd. All rights reserved.