Exudate gums: chemistry, properties and food applications - a review

Gums are complex carbohydrate molecules which have the ability to bind water and form gels at low concentration. These carbohydrates are often associated with proteins and minerals in their structure. Gums are of various types such as seed gums, exudate gums, microbial gums, mucilage gums, seaweeds gums, etc. Exudate gums are plant gums which ooze out from bark as a result of a protection mechanism upon injury. Exudate gums have been used by humans since ancient times for various applications due to their easy availability. The main characteristics which make them fit for use in various applications are viscosity, adhesive property, stabilization effect, emulsification action and surface-active property. Major applications of these gums are in food products, the paper, textile, cosmetics and pharmaceutical industries, oil-well drilling, etc. In the present paper, the chemistry, properties, processing and applications of commercially available exudate gums such as acacia gum or gum arabic, karaya gum, ghatti gum and tragacanth gum are discussed. Recent literature reveals that apart from the above mentioned applications, these gums also have nutritional properties which are being explored. Other gums cannot replace them because of their certain unique characteristics. © 2020 Society of Chemical Industry.

Shake No Bake: A Homemade Ultrasound Gel Recipe for Low-Resource Settings

Commercially produced ultrasound coupling gel is often a scarce resource in rural regions of low-income countries that use sonography as their main imaging modality and, when available, may be cost prohibitive. Various homemade gels were created and tested to assure image quality was not compromised. Glucomannan-based gel and guar gum-based gel had superior physical properties in initial testing and showed no substantial difference compared with commercially available ultrasound gel on subject and phantom imaging and analysis (P > .05 using a 1-tailed sign test). Neither gel required heating, attracted insects, damaged ultrasound transducers, stained samples of clothing, or had harmful effects to subjects.

Influence of twin-screw extrusion on soluble arabinoxylans and corn fiber gum from corn fiber

BACKGROUND

The effect of feed moisture content and screw speed in the extrusion process with and without chemical pretreatment of corn fiber was investigated. Different chemical pretreatment methods (NaOH and H2 SO4 solution) were compared. The improvement of reducing sugar, soluble arabinoxylans (SAX) content and the yield of corn fiber gum was measured.

RESULTS

A high reducing sugar content was obtained in the filtrate fraction from the extruded destarched corn fiber (EDCF) with H₂SO₄ pretreatment. Feed moisture content most effectively improved both reducing sugar and SAX content of filtrate. Increasing feed moisture content and screw speed resulted in a higher SAX content in the filtrate of the EDCF with NaOH pretreatment. The SAX content of the residual solid from the EDCF with NaOH pretreatment was higher compared to H₂SO₄ pretreated and unpretreated samples and significantly increased with decreasing feed moisture content. The screw speed did not have a major impact after enzyme hydrolysis. The yield of corn fiber gum was increased by 12% using NaOH pretreatment combined with extrusion process as compared to the destarched corn fiber.

CONCLUSION

The results show the great potential of the extrusion process as an effective pretreatment for disruption the lignocelluloses of corn fiber, leading to conversion of cellulose to glucose and hemicelluloses to SAX and isolation of corn fiber gum.

Process design and economic analysis of a hypothetical bioethanol production plant using carob pod as feedstock

A process for the production of ethanol from carob (Ceratonia siliqua) pods was designed and an economic analysis was carried out for a hypothetical plant. The plant was assumed to perform an aqueous extraction of sugars from the pods followed by fermentation and distillation to produce ethanol. The total fixed capital investment for a base case process with a capacity to transform 68,000 t/year carob pod was calculated as 39.61 millon euros (€) with a minimum bioethanol production cost of 0.51 €/L and an internal rate of return of 7%. The plant was found to be profitable at carob pod prices lower than 0.188 €/kg. An increase in the transformation capacity of the plant from 33,880 to 135,450 t/year was calculated to result in an increase in the internal rate of return from 5.50% to 13.61%. The obtained results show that carob pod is a promising alternative source for bioethanol production.