FSHW: Gelatin stable traditional emulsion: emulsion form, droplet and storage stability

Original title: FSHW: Gelatin stable traditional emulsion: emulsion form, droplet and storage stability
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-3 unsaturated fatty acids are important nutrients. Fish oil is known to be rich in these fatty acids, such as DHA and pyrethrene (EPA). As a result, fish oil has been considered one of the most promising materials in the food and pharmaceutical industry in recent years. However, fish oil can easily lose its nutritional properties due to unstable double bonds after exposure to light, oxygen or heat. In addition, if added directly to the food, the taste of fish oil will affect the flavor of the food. Due to the poor water solubility of fish oil, it cannot be added directly to water-related foods. Therefore, it is necessary to develop new dosage forms such as food emulsions to deal with the shortcomings of fish oil.
collagen is the most important insoluble fibrin in mammalian connective tissue and has a key physiological effect. Gelatin is the product of partial hydrolysing of primary collagen. Collagen and gelatin have been widely studied and used in the food and pharmaceutical industries, bioimaging and tissue engineering. Gelatin-stable emulsions have been shown to inhibit the oxidation of fish oil. Recently, gelatin has been used in emulsion preparation as cross-linked gelatin particles, gelatin/shell polysaccharide complexes or gelatin/glucosin/tynanic acid nanocomposomes to encapsulate sunflower oil, corn oil or medium chain triglycerides. Cross-linked gelatin nanoparticles and mixed gelatin/surfactants have been studied to stabilize fish oil load emulsions. Functional gelatin has also been developed to improve the stability of gelatin stabilization emulsions. Gelatin can also be used in the preparation of a stable water-packed oil multi-layer lotion consisting of gelatin-gel double layer and
β
-lactoglobulin-
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-cara glue-gelatin three layers. Gelatin/glue stable multi-layer emulsion can be used in the preparation of electrowoven nanofibers. However, these efforts did not systematically study pure gelatin stable emulsions. Therefore, due to the low cost of products, the production process is suitable, the use of pure gelatin preparation of traditional emulsion is a better choice for the food industry.
emulsion form can be divided into liquid, re-dispersable emulsified gel and non-dispersable emulsified gel. Emulsified gel is a soft solid material. Re-dispersable emulsified gels are emulsified gels that can be re-dispersed into liquid emulsions under certain conditions. After successful preparation of emulsion gel, it can be easily and steadily transported and stored. However, the shape of emulsion must be studied to understand its storage requirements and potential applications. The re-dispersion of the emulsion gel should be considered before it is applied in practice. Recent studies have shown that the distribution of emulsion morphology and droplet size depends on the emulsion used and storage time. Therefore, In this work, Mengzhen Ding and Jian Zhong of Shanghai Ocean University, National Freshwater Aquatic Products Processing Technology Research and Development Center (Shanghai) mainly study the effects of gelatin on the preparation method and storage conditions of traditional emulsions that stabilize fish oil loads on emulsion morphology, droplets and storage stability.
effect of gelatin solution
pH
on the stable traditional emulsion of fish oil load gelatin
the traditional emulsion with different pH values (3, 5, 7, 9, 11) is homogenous at 60 s at 11,500 r/min. After preparation, there was no significant change in pH, indicating that homogenization had no significant effect on emulsion pH. These lotions (Figure 1) are milky white or pale pink (pH 11), which is the result of gelatin distribution in a strong alkaline solution. The freshly prepared lotion consists of droplets (Figure 1C), the size of which is distributed in three segments and decreases linearly as the pH of the solution increases (Figure 1C). In the CLSM experiment, Nile red and nile blue were used for dyeing fish oil and gelatin, respectively. THE CLSM results show that fish oil (red) is wrapped in gelatin (blue) to form droplets in the water phase (Figure 2A). Therefore, the fish oil load gelatin stable traditional emulsion can be successfully prepared under pH 3 to 11 conditions. The effect of pH on droplet size may be due to differences between the pH of the solution and the isoelectre of gelatin. Previous work has shown that the solution has a significant effect on the physical stability of the yelp-rich emulsion, causing droplet aggregation at pH 4 and pH 5. However, the accumulation of droplets was not shown in this study. With the increase of pH of the solution, the negative charge of gelatin increases, the hydrophobic zone (shell layer)-hydrophobic zone (oil core) ratio of gelatin molecules increases, and the curvature of droplets increases; But this is the opposite of the pH effect of many water-wrapped emulsions. After storing 3 d at 4 degrees C, emulsification occurs in traditional emulsions (Figure 1B). Emulsification index values are: pH 11 (CI: (34.6±1.5)%) >pH 3 (CI: (19.4±1.0%)) >pH 5 (CI: (CI: 15.3±1.0%)) >pH 7 (CI: (6.7±0.4)) >pH 9 (CI: (4.5±0.5%). Traditional emulsions become gels at pH 7 and pH 9 and can be re-dispersed after incubation of 5 min at 45 degrees C. Therefore, a higher gelatin solution pH induces the conversion of emulsions from liquid forms to re-dispersable gel forms. This will facilitate the storage and transport of emulsions, which can be transported from raw material plants to food processing plants in the form of gels and then re-dispersed into liquid forms for food production. After storage of 3 d (Figure 1C), the size of the droplets in the traditional lotion at pH 9 did not change significantly, while the droplet size increased at pH 3, 5, 7, 11. The traditional emulsion droplets with gelatin pH in the range of 7 to 11 are relatively stable (Figure 2), while the gelatin pH has some holes in the traditional emulsion droplets in 3 and 5 (Figure 2B), indicating that a variety of emulsions have been formed. Type B gelatin is an alkaline processed gelatin with an isoelectrelectring point of 4.8 to 5.1. Proteins may aggregate when the emulsion pH is close to its isoelectrent point. This may be the main reason why the emulsion prepared by gelatin at pH 3 and pH 5 is relatively unstable, and type B gelatin tends not to congreate when pH is away from isoelectens. This may explain why traditional lotions transition between liquid and gel forms. According to the optical microscope image, the emulsion gel may be a protein-stable emulsion gel - a aggregated particle gel. Taking into account emulsification (Figure 1) and droplet structure (Figure 2), gelatin-stabilized traditional emulsions are used for follow-up work at pH 9.
A.-B. traditional lotions are stored at 0 h and 4 degrees C, respectively. Images in glass bottles; C. Inverted optical microscopes observe images of traditional emulsion droplets stored at 0 h and at 4 degrees C after 3 d.
1 observed the traditional emulsion of the oil load stability (1.0%) at different gelatin solution pHs (3, 5, 7, 9 and 11)
A. Traditional emulsion droplets at 0 h; Storage of 3 d after the traditional emulsion droplets at 4 degrees C.
Figure 2 Fish oil load gelatin stabilization (1.0%) traditional emulsion at different gelatin solution pH (3, 5, 7, 9 and 11) CLSM image
fish oil load gelatin latex gel re-dispersion Process
3 d at 4 degrees C, the traditional emulsion at pH 7 to 9 can form emulsion gel (Figure 1, Figure 2 with black arrows and black asterisks), can be re-dispersed at 45 degrees C to form liquid emulsion 5 min. The re-dispersion process is further analyzed. After storing 1 d at 4 degrees C, the liquid emulsion (Figure 3A, 3B) becomes a gel emulsion consisting of droplets (Figure 3F) (Figure 3C). The gel formation process did not significantly change the shape and size of the droplets. After incubation of 5 min at 45 degrees C, the gel becomes liquid (Figure 3D). The re-dispersed emulsion droplets (Figure 3G) are similar to freshly prepared emulsions (Figure 3E) and emulsion gels (Figure 3F). These results show that neither the gel formation process nor the re-dispersion process affects the structure (shape and size) of the droplets. It is important to note that the re-dispersion emulsion gel in this study is solid, unlike other re-dispersed emulsion powders that use spray drying techniques in their work. The preparation of the dispersed emulsion gel only needs to be left still for a period of time and does not require the use of complex instruments. In addition, the shape of the emulsion gel can be controlled by designing a liquid emulsification container. Therefore, re-dispersing emulsified gels may have good potential in the emulsification industry.
the traditional emulsion at A. 0 h; Inverted conventional emulsion gel after storage of 1 d at 4 degrees C, D. inverted conventional emulsion re-dispersed at 45 degrees C 5 min; E. 0 h emulsion droplet inverted optical microscope image; F. inverted optical microscope image of emulsion droplets in traditional emulsion gel; and G. inverted optical microscope image of emulsion droplet re-dispersion emulsion.
Figure 3 The re-dispersion process of fish oil load gelatin (1.0%) emulsion gel
This study determines the effect of preparation method and storage conditions on the emulsion form, droplet and storage stability of gelatin stabilizing fish oil load traditional emulsion, and analyzes the re-dispersion process. The results show that traditional lotions can be successfully prepared and modified. Increased pH, storage temperature and storage time of gelatin solutions have led to the transformation of these emulsions from liquid to re-dispersable gel states. These droplets are mainly three-state distribution. Their size decreases linearly with the increase of gelatin solution pH and homogeneity time, and decrease exponentially with the increase of homogeneity velocity. The various forms of these lotions (liquid emulsions, re-dispersable emulsion gels and non-dispersable emulsion gels) allow for a wide range of potential applications in food and beverages, folly and other foods. Understanding these forms will facilitate the determination of optimal emulsion storage and transport conditions. Many forms of emulsion may be related to gelatin properties, such as its film-forming behavior and gel-prone properties.