Ca-alginate liquid core capsule for lactobacili fermentation

Lactic acid bacteria (LAB) have been used for food fermented products since ancient time, which not limited to dairy products. Some Asian traditional food is produced through LAB fermentation. LAB consist of the Gram-positive genera including lactobacillus, which produce lactic acid as the end product of a carbohydrate fermentation. Lactobacillus is one of the important LAB that have been widely applied in food fermentation because of their fermentative ability to enhance food safety, nutrition and to improve health related benefits (as probiotics bacteria). Lactobacillus also received much attention for lactic acid production. This is because lactic acid is highly demanded for the production of poly-l-lactate biodegradable plastics in recent days. The viability and microbial growth of Lactobacilli have been known to be inhibited by its end product (i.e. lactic acid). One of the common solutions to overcome the inhibition issue is by using encapsulation technology. Encapsulation offers several advantages for lactobacilli fermentation which included protection to the bacterial from harsh environments (e.g. pH, temperature, shear stress), retaining cells in continuous process, and allowing reuse of the bacteria. Encapsulation can be achieved in two forms; beads or capsules. Apart from beads, the capsules consisted of a defined inner core which surrounded by a semi permeable membrane. The content of the inner core could be in the form of liquid or solid. Liquid core capsules provide plenty of space for microbial growth (in inner core), eliminate cell release to fermentation medium and minimize mass transfer resistance of solutes. The main focus of this review was on the liquid core capsules produced by Ca-alginate bio-gel. In general, Ca-alginate liquid core capsules can be produced using single step methods or multiple steps methods. The details of the method used to produce the liquid core capsules were described and discussed. The use of the capsules for lactobacilli fermentation is limited because they are easily destabilized by chelating agents and eventually dissolved. The counter measures to strengthen the stability of the capsules were discussed. The previous studies showed that the viability, microbial growth and productivity of the encapsulated lactobacilli (in liquid core capsule) were better than those of either free cell and entrapped lactobacilli (in beads). Lastly, the authors give several recommendations to expand the potential of using the liquid core capsules to improve Lactobacilli fermentation

Calcium Pectinate Beads Formation: Shape and Size Analysis

The aim of this study was to investigate the inter-relationship between process variables and the size and shape of pectin solution droplets upon detachment from a dripping tip as well as Ca-pectinate beads formed after gelation via image analysis. The sphericity factor (SF) of the droplets was generally smaller than 0.05. There was no specific trend between the SF of the droplets and the pectin concentration or the dripping tip radius. The SF the beads formed from high-concentration pectin solutions and a small dripping tip was smaller than 0.05. The results show that the Reynolds number and Ohnesorge number of the droplets fall within the operating region for forming spherical beads in the shape diagram, with the exception to the lower boundary. The lower boundary of the operating region has to be revised to Oh = 2.3. This is because the critical viscosity for Ca-pectinate bead formation is higher than that of Ca-alginate beads. On the other hand, the radius of the droplets and beads increased as the dripping tip radius increased. The bead radius can easily be predicted by Tate's law equation

3D food printing of as the new way of preparing food: A review

The 3D printing technology has been applied to directly to construct physical model from 3D modelling without any aid of mold. Several industries such as automobile, aerospace including and recently food industry has utilize this technology to manufacture a complicated and intricate part required in the industry. It is foreseeable that 3D food printing (3DP) are possible to produce complex food model with unique internal pattern. A 3D food printing technique is composed of an extrusion-based printing, selective laser sintering and inkjet (liquid binding) printing. The food materials such as sugar, gelatin-based chocolate, and are used to create designed shape based on layer-by-layer method. This paper presents a review of 3D food printing techniques. This review is to categorize, printability, productivity, properties of printable material and mechanism of 3D food printing techniques, as well as to propose the future direction of this novel technology

Influence of process variables and formulation composition on sphericity and diameter of Ca-alginate-chitosan liquid core capsule prepared by extrusion dripping method

The influence of process variables and formulation composition on the sphericity and diameter of the alginate capsules which contained dual cations (Ca-and-chitosan) are characterized in this study. Capsule sphericty was not influenced by needle diameter but instead, capsule diameter increased proportionally with the needle diameter. The combined effects of the liquid core solution and alginate solution on the sphericity of the capsules are tabulated. Spherical capsules can be produced when the following criteria were fulfilled: stirring speed is in the range of 240–300 rpm; calcium chloride concentration is >5 g/L; viscosity of liquid core solution is >203 mPa.s; as well as viscosity of alginate solution is in between 47 and 386 mPa.s. The capsule diameter was predicted using a modified Tate’s law equation and an error analysis was conducted to evaluate the equation. The predicted diameter was well correlated with the experimental data with an average absolute deviation <3.6%

Formation Of Chitosan-Alginate Capsules Using Extrusion-Dripping Method: Effect Of Stirring Speed And Biopolymers Types

Abstract: The aim of this study was to investigate the effect of stirring speed and biopolymer types on size and shape of chitosan-alginate capsules produced through extrusion-dripping method. Chitosanalginate capsules were produced by extruding chitosan-calcium chloride solution into sodium alginate solution. As a result, capsules with defined inner core and membrane were formed. Under the tested conditions, chitosan-alginate capsules with diameter in a range of 3.6 mm to 4.1 mm were produced. The result shows that the shape of chitosan-alginate capsules was significantly affected by the stirring speed. At the stirring speed of 600 rpm, mainly small and spherical capsules were produced. It was found that chitosan-alginate capsules produced from guluronic acid-rich alginate (AHG) were larger in term of diameter and membrane thickness as compared to those produced from mannuronic acid-rich alginate (AHM). The molecular weight of chitosan has no significant effect on diameter, shape and membrane thickness of the capsules

Do Termites Avoid Carcasses? Behavioral Responses Depend on the Nature of the Carcasses

BACKGROUND: Undertaking behavior is a significant adaptation to social life in enclosed nests. Workers are known to remove dead colony members from the nest. Such behavior prevents the spread of pathogens that may be detrimental to a colony. To date, little is known about the ethological aspects of how termites deal with carcasses. METHODOLOGY AND PRINCIPAL FINDINGS: In this study, we tested the responses to carcasses of four species from different subterranean termite taxa: Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe) (lower termites) and Microcerotermes crassus Snyder and Globitermes sulphureus Haviland (higher termites). We also used different types of carcasses (freshly killed, 1-, 3-, and 7-day-old, and oven-killed carcasses) and mutilated nestmates to investigate whether the termites exhibited any behavioral responses that were specific to carcasses in certain conditions. Some behavioral responses were performed specifically on certain types of carcasses or mutilated termites. C. formosanus and R. speratus exhibited the following behaviors: (1) the frequency and time spent in antennating, grooming, and carcass removal of freshly killed, 1-day-old, and oven-killed carcasses were high, but these behaviors decreased as the carcasses aged; (2) the termites repeatedly crawled under the aging carcass piles; and (3) only newly dead termites were consumed as a food source. In contrast, M. crassus and G. sulphureus workers performed relatively few behavioral acts. Our results cast a new light on the previous notion that termites are necrophobic in nature. CONCLUSION: We conclude that the behavioral response towards carcasses depends largely on the nature of the carcasses and termite species, and the response is more complex than was previously thought. Such behavioral responses likely are associated with the threat posed to the colony by the carcasses and the feeding habits and nesting ecology of a given species