Loulouda Bosnea

Whey valorisation: a complete and novel technology development for dairy industry starter culture production.

Whey is the major by-product of the dairy industry, produced in large quantities and usually disposed off causing major environmental pollution, due to its high organic load that makes treatment cost prohibitive. This paper comprises a contribution on the valorisation of this high polluting liquid waste of the dairy industry, based on research for the production of novel dairy starter cultures using whey as raw material. Starter cultures are used for cheese ripening in order to: (i) accelerate ripening, (ii) improve quality and (iii) increase shelf-life. The developed technology involves biomass production from whey followed by thermal drying of cultures. Specifically, Kluyveromyces marxianus, Lactobacillus bulgaricus and kefir yeasts were thermally dried, and their efficiency in lactose and milk whey fermentations was studied. The most suitable culture regarding its technological properties was kefir, which was used for cheese ripening in freeze-dried and thermally dried form. Besides the reduction of production cost, which is an essential requirement for the food industry, the use of thermally dried kefir displayed several other advantages such as acceleration of ripening, increase of shelf-life, and improvement of hard-type cheese quality.

Progress in bacterial cellulose matrices for biotechnological applications

Bacterial cellulose (BC) is an extracellular polymer produced by many microorganisms. The Komagataeibacter genus is the best producer using semi-synthetic media and agricultural wastes. The main advantages of BC are the nanoporous structure, high water content and free hydroxyl groups. Modification of BC can be made by two strategies: in-situ, during the BC production, and ex-situ after BC purification. In bioprocesses, multilayer BC nanocomposites can contain biocatalysts designed to be suitable for outside to inside cell activities. These nanocomposites biocatalysts can (i) increase productivity in bioreactors and bioprocessing, (ii) provide cell activities does not possess without DNA cloning and (iii) provide novel nano-carriers for cell inside activity and bioprocessing. In nanomedicine, BC matrices containing therapeutic molecules can be used for pathologies like skin burns, and implantable therapeutic devices. In nanoelectronics, semiconductors BC-based using salts and synthetic polymers brings novel films showing excellent optical and photochemical properties.

Potential effects of probiotics in cheese and yogurt production: A review

The implementation of probiotic cultures in the dairy industry has been a modern trend in the last few years. The main reasons are the enhancement of human nutrition and health and better organoleptic properties of food products. Probiotic microorganisms can provide protection against pathogenic microorganisms in the gut, by reducing the severity of some types of diarrhea, and against the risk of atopic eczema in high‐risk infants. They also assist in the development of the immune system, by improving colonic health and nutrition. This has led to a better acceptance by the consumers, since it has been demonstrated recently that the microorganisms of the respective food products are also present in the natural microflora of the gut. This review discusses the criteria to select probiotic microorganisms as well as their positive impact on cheese and yogurt production.

Fermentation efficiency of thermally dried kefir

Three thermal drying methods (conventional, vacuum and convective) were used for drying of kefir biomass and their effect on cell viability, fermentation rate and other kinetic parameters of lactose and whey fermentation were studied. Convective drying rate was higher than conventional and even higher than vacuum at each studied temperature (28, 33 and 38 degrees C). After that, fermentations were performed by kefir biomass dried by the three drying methods. Ethanol concentration, ethanol productivity and ethanol yield are higher in whey fermentations performed by kefir biomass dried with convective drying method. Regarding lactic acid production, fermentation performed by kefir biomass dried with conventional drying method gave higher concentrations, compared to other drying methods. Storage of kefir biomass convectively dried at 33 degrees C for 4months, without any precaution decreases its fermentability and thus reduces ethanol (31%) and lactic acid productivity (20%), but remains a promising technology, since a significant part of its initial fermentative activity is retained.

CHAPTER 47:Technology and Biotechnology of Lactose Contained in Raw Food Materials

Lactose is the principal carbohydrate in milk and cheese whey. Whey is the major by-product of the dairy industry and represents a major source of environmental pollution due to the bulk quantities and its high organic load. Since lactose is the major component of whey solids contributes significantly to its high biochemical and chemical oxygen demand. Recently, developments in process technology and biotechnology of lactose have been accompanied by massive changes in dairy industrys operations leading in a extensive range of dairy and other novel related products. Furthermore, considerable efforts have been made over the years to explore new outlets for lactose utilization and make whey a potential raw material for the production of various biotechnological products. The increasing economic value of these products worldwide increased basic research in lactose technology and biotechnology. This chapter is attempts to summarize some of the technological and biotechnological methods used for lactose over the years, emphasizing in the importance of the available options such as lactose fermentation for the production of bioethanol, biogas, bio-surfactants, SCP production, etc.