ORIGINAL PAPER Effect of frozen storage on emulsifying properties of actomyosin from mantle and ﬁns of squid (Illex argentinus) L. A. Mignino • M. C. Toma ´s • M. E. Paredi Received: 4 March 2011 / Revised: 20 May 2011 / Accepted: 6 June 2011 / Published online: 9 July 2011 Ó Springer-Verlag 2011 Abstract The emulsifying properties of actomyosin (AM) of mantle and ﬁns obtained periodically from frozen- stored squid were investigated. Oil in water (O/W) emulsions and their stability were studied by optical characterisation. Both emulsions showed that the initial backscattering (BS) decreased after 3 months of frozen storage. O/W emulsions formulated with AM of squid mantle showed certain stability during the ﬁrst 20 min, and presented destabilisation during the remaining analysed time, reaching a 20% of BS, approximately. However, for emulsions formulated with AM of ﬁns, the BS diminution was recorded between 30 and 45 min, indicating a higher stability as a function of time with respect to the mantle. The size distribution of emulsions prepared after short times of storage presented three droplet size populations. With increasing the time of frozen storage, the size dis- tribution changed from trimodal to bimodal: the large population decreased until it disappeared and the popula- tion with medium size increased at long time of frozen storage. The emulsions formulated with AM of squid ﬁns presented a similar behaviour than emulsions of mantle. QuickScan proﬁles allowed discriminating creaming and coalescence processes to both emulsions mainly at short time of frozen storage. The emulsion prepared with AM from squid ﬁns was further ﬂocculated than emulsion of mantle. Actomyosin from ﬁn squid exhibits the best properties as emulsiﬁer agents of O/W emulsions. These results suggest that a short frozen-storage period can favour the emulsifying properties of actomyosin obtained from squid mantle and ﬁns. On the other hand, the structure of ﬂocs would affect positively the stability of emulsions. Keywords O/W  Emulsions  Actomyosin  Squid  Frozen storage Introduction Illex argentinus is the most important species of cephalo- pods in South American seas, according to its potential yield and exportation volume shown in the recent years, i.e. about 255,000 tons, close to the Merluccius hubbsi [1]. For this reason, it constitutes a very interesting economic resource for exploitation and industrialisation. In addition, squid represents an important source of proteins, from the nutritional point of view, and it offers many advantages over other seafood, such as a high post-processing yield, very low fat content, bland ﬂavour and very white ﬂesh [2]. In general, proteins rank among the most used compo- nents for food preparation due to their desirable attributes [3]. Proteins have a strong tendency to be adsorbed at oil– water interfaces forming thick viscoelastic ﬁlms, which are responsible for stabilizing most of food emulsions against ﬂocculation and coalescence [4]. The ability of proteins to L. A. Mignino  M. E. Paredi (&) Facultad de Ciencias Agrarias (UNMDP), Ruta 226, Km. 73,5, Balcarce, Bs. As, Argentina e-mail: elima_1930@yahoo.com.ar M. E. Paredi Comisio ´n de Investigaciones Cientı ´ﬁcas (CIC), Buenos Aires, Argentina M. C. Toma ´s Centro de Investigacio ´n y Desarrollo en Criotecnologı ´a de Alimentos (CIDCA), Calle 47 y 116, La Plata, Buenos Aires, Argentina L. A. Mignino  M. C. Toma ´s Consejo Nacional de Investigaciones Cientı ´ﬁcas y Te ´cnicas (CONICET), Buenos Aires, Argentina 123 Eur Food Res Technol (2011) 233:437–445 DOI 10.1007/s00217-011-1519-4