A microbiological, physicochemical, and texture study during storage of yoghurt produced under isostatic pressure
Abstract This work aimed to study refrigeration storage (4 °C for 23 days) of yoghurt produced at 43 °C under sub-lethal high pressure, at 10, 20, 30 and 40 MPa, in comparison with the fermentation process at atmospheric pressure (0.1 MPa). Lactic acid bacteria (S. thermophilus and L. bulgaricus, LAB) and quality parameters like pH, titratable acidity, syneresis and colour were evaluated, along with textural analyses to infer how pressure would impact the obtained yoghurt along storage. Higher fermentation pressures resulted in slightly lower LAB loads (a maximum of 1.01 Log (CFU/mL)) and increased the fermentation time (a maximum of 3 h 25 min), syneresis (a maximum of 44%), all for 40 MPa…
Fermentation at non-conventional conditions in food- and bio-sciences by the application of advanced processing technologies
The interest in improving the yield and productivity values of relevant microbial fermentations is an increasingly important issue for the scientific community. Therefore, several strategies have been tested for the stimulation of microbial growth and manipulation of their metabolic behavior. One promising approach involves the performance of fermentative processes during non-conventional conditions, which includes high pressure (HP), electric fields (EF) and ultrasound (US). These advanced technologies are usually applied for microbial inactivation in the context of food processing. However, the approach described in this study focuses on the use of these technologies at sub-lethal levels,…
Utilization of glycerol during consecutive cycles of Lactobacillus reuteri fermentation under pressure: The impact on cell growth and fermentation profile
Abstract Exposure of bacterial cells to sub-lethal high pressure (HP) during growth and fermentation may promote development of new adaptive features, with potential biotechnological interest. The present work evaluated the effect of consecutive fermentation cycles under HP on Lactobacillus reuteri growth and glycerol/glucose co-fermentation. At all conditions tested (0.1, 10 and 25 MPa), 1,3-propanediol production from glycerol was enhanced over the cycles. The highest titers, yields and productivities were achieved at 10 MPa. In addition, the HP-cycles promoted shifts in by-product formation (ethanol, acetate and lactate), with different profiles according to the pressure. Ratios between …
Hyperbaric Storage of Fruit Juice and Impact on Composition
International audience; One of the main parameters affecting fruit juice preservation is the temperature over storage. Spoilage is further delayed by reducing the temperature, which although valuable, leads to high energy costs. Recently, hyperbaric storage has appeared as an alternative preservation methodology by a microbial growth inhibition similarly to refrigeration storage, showing great potential for energy savings, as well as carbon footprint reduction, as it could be applied at room temperature. Recent publications revealed the possibility to preserve fruit juice under pressure at variable/uncontrolled room temperature, meaning that energy is only required in the compression/decomp…
Innovative non-thermal technologies affecting potato tuber and fried potato quality
Abstract Background Potatoes are important tubers for human consumption, providing an essential source of energy and great nutritional characteristics for human health. However, before consumption, potato tubers need to be stored and processed. As frying is the most common technique used in potato processing, fried potato is the most important processed potato product. Some food characteristics, provided by the frying process, are considered desirable, but others are harmful to human health and, thereby the main challenge is to reduce the formation of the undesirable characteristics, without compromising the sensorial attributes. Scope and approach In this review, the origin, economic impor…