Characteristics, Stability, and Release of Peanut Sprout Extracts in Powdered Microcapsules by Spray Drying

Abstract

This study was carried out to investigate the characteristics of powdered microcapsules from peanut sprout extracts prepared by spray drying. The microcapsules were made from medium-chain triglyceride (MCT) as primary coating material and whey protein concentrate (WPC) or maltodextrin (MD) as selected secondary coating materials. The microcapsule studies conducted were microphotograph, scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR), particle size, moisture contents, sorption, zeta potential, storage stability, and in-vitro study. The surface of microcapsules coated with WPC were rough and smooth, and particle size ranged from 2.86 to 8.59 lm. An FT-IR study revealed that absorption bands at 1,537 and 1,657 cm À1 of microcapsules can be attributed to the protein amide I and II bands of WPC overlapped by the conjugated C=C. The moisture content was 1.33% in the microcapsules coated with WPC. The moisture sorption increased until 18% at the 90% RH. The yield of peanut sprout extracts from microcapsules was 89.01%. In the in-vitro study, the microcapsules released 2.48 and 6.01% at pH 2.0 and 4.0, respectively, in simulated-gastric fluid, and 61.07 and 89.24% at pH 6.0 and 8.0, respectively, in simulated-intestinal fluid. The preservation rate of the microcapsules dropped down to 60.43% from 89.01% during six months of storage. The stability of peanut sprout extracts in the microcapsules was over 80% at 4 and 20 C during 10-day storage. The zeta-potential of microcapsules was stable with À30 mV. Based on the data obtained from the present study, the powdered peanut-sprout-extract microcapsules coated with WPC exhibited high stability during storage. Therefore, the powdered microcapsules by spray drying may be useful as a functional ingredient.

Microencapsulation of borage oil with blends of milk protein, β‐glucan and maltodextrin through spray drying: physicochemical characteristics and stability of the microcapsules

“…These dents may cause wall materials to contain large amounts of MD, which reduces the viscoelasticity of wall materials and shrink the particles during drying and cooling . Similar results were reported by Rodea‐González et al ., Lee et al . and Kuang et al .…”

“…The moisture contents of the microcapsule powders prepared with different wall materials are listed in Table 2 and expressed as grams of contained moisture per kilogram of microcapsule powder. The moisture contents of the samples ranged from 9.3 g kg -1 to 16.2 g kg -1 , which is consistent with the moisture contents of 13.3-16.5 g kg -1 in the WPC-or MD-encapsulated powdered microcapsules reported by Lee et al 34 These moisture contents are below the minimum moisture specification of dried powder in the food industry (30-40 g kg -1 ). 35 The two types of complex wall materials (CAS-MD and WPC-MD) presented moisture contents slightly higher than those of other wall materials.…”

“…These dents may cause wall materials to contain large amounts of MD, which reduces the viscoelasticity of wall materials and shrink the particles during drying and cooling. 39 Similar results were reported by Rodea-González et al, 7 Lee et al 34 and Kuang et al 44 Some small particles attached to the surface of large particles in the microcapsules. This effect was possibly a result of the presence of surface liquid, which promoted the weak distribution of properties of the microcapsules and the aggregation of particles.…”

“…A positive correlation exists between molar mass and T g . GLU increased T g because of its high molar mass (31 000–237 000 g mol –1 ) . The powders prepared with GLU presented a relatively high T g that is more stable during processing and storage.…”

“…43 GLU increased T g because of its high molar mass (31 000-237 000 g mol -1 ). 34 The powders prepared with GLU presented a relatively high T g that is more stable during processing and storage. This result confirmed that GLU holds a promising application as wall material in the food industry.…”