Subscriber access provided by AUSTRALIAN NATIONAL UNIV
Article
Solid-in-oil-in-water emulsions for delivery of lactase to control in vitro hydrolysis of lactose in milk Yun Zhang, and Qixin Zhong J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.7b03787 • Publication Date (Web): 05 Oct 2017 Downloaded from http://pubs.acs.org on October 7, 2017
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
Journal of Agricultural and Food Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 30
Journal of Agricultural and Food Chemistry
1
Solid-in-oil-in-water emulsions for delivery of lactase to control in vitro hydrolysis of
2
lactose in milk
3
Yun Zhang and Qixin Zhong*
4
Department of Food Science, University of Tennessee, Knoxville, TN 37996
5 6 7 8
Please send correspondence to
9
*Qixin Zhong, Professor
10
Department of Food Science
11
The University of Tennessee
12
2510 River Drive
13
Knoxville, TN 37996
14
USA
15
Phone: 1 (865) 974-6196; Fax: 1 (865) 974-7332
16
E-mail:
[email protected] 17
1 ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
18
19
Page 2 of 30
Abstract There is an established need to deliver lactase in milk to retain activity during storage and
20
hydrolyze lactose after ingestion. In the present work, spray-dried lactase powder was
21
encapsulated in solid-in-oil-in-water (S/O/W) emulsions to fabricate delivery systems. The
22
adoption of Span® 80 in milk fat and lecithin in protein solution enabled the encapsulation of ~76%
23
lactase and droplets smaller than 400 nm. Additional cross-linking proteins on droplets by
24
transglutaminase and addition of sodium caseinate effectively reduced the amount of free lactase
25
after spray drying emulsions. When compared to free lactase, encapsulation significantly
26
improved the thermal stability of lactase, reduced the lactose hydrolysis during 14-day
27
refrigerated storage (~70% vs. 0.05) for the two treatments with the two O:W
230
volume ratios.
11 ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
231
The emulsion droplets were considerably smaller than the >1 µm dimension of spray-
232
dried powder (supplementary Figure S1), which indicated the breakup of the powder during
233
blending to prepare the S/O suspension. Droplets had a dimension (Table 1) comparable to the
234
40-300 nm diameter of casein micelles and the ~600 nm diameter of fat globules in homogenized
235
milk.26 The droplets in the present study were much smaller than the micrometer-scale droplets
236
in S/O/W systems encapsulating spray-dried glutamine 16 and probiotics.17, 27 This resulted from
237
the reduced S/O and O/W interfacial tensions by Span® 80 in MF 28 and the synergistic
238
emulsifying activity of NaCas and lecithin in the aqueous phase.29
239
Encapsulation efficiency (EE)
240
The EEs of the two treatments are also summarized in Table 1. The EE was higher at a
241
lower volume fraction of MF, which corresponded to significantly smaller droplets (Table 1; P
