Influence of ultrasound frequency and power on lactose nucleation. (May 2019)

• Record Type: Journal Article
• Authors: Sánchez-García, Yanira I.; Ashokkumar, Muthupandian; Mason, Timothy J.; Gutiérrez-Méndez, Néstor
• Is Part Of: Journal of food engineering. Volume 249(2019)
• Page Start: 34
• Page End: 39
• Publication Date: 2019-05
• Subjects: Lactose nucleation -- Ultrasound frequency -- Ultrasound power -- Lactose crystallization -- Sonocrystallization of lactose; Food industry and trade -- Periodicals; Food -- Analysis -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Analyse -- Périodiques; Aliments -- Recherche -- Périodiques; 664.005
• DOI: 10.1016/j.jfoodeng.2019.01.007
• Languages: English
• ISSNs: 0260-8774

Abstract

Abstract: This work was aimed at studying the effect of different ultrasound frequencies (20, 44, 98, 142 kHz) and ultrasound powers (10, 20, 30 W) on lactose nucleation. For this purpose, lactose solutions (25% w/v) with traces of whey proteins (0.3%) were sonicated 300 s. Crystallization was induced by reducing the temperature from 30 to 15 °C, which increased the absolute supersaturation of lactose ( C α - C αs ) from 0.19 to 8.25 g 100 g −1 . The nucleation of lactose was monitored by light scattering. Results showed that application of ultrasound (US) modified both, the molecular-attachment frequency to form new nuclei ( k ) and the induction time. The ultrasound effect on lactose nucleation varied depending on the US-frequency or power applied. The most noticeable changes were observed at 44 kHz (11.13 J mL −1 ) since the number of nuclei formed ( a ) raised, the k -value increased to 0.1482 s −1, and the induction time decreased to 15 s. Highlights: In non-sonicated crystallization, nucleation of lactose was slow with few nuclei. Lactose nucleation was most affected at 44 kHz of ultrasound frequency and 20 W Crystallization at 44 kHz accelerated the nucleation and reduced the induction time. Crystallization at 20 W increased the nuclei and lowered the induction time. The whey proteins modified the nucleation of lactose in sonocrystallization.