Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films

Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91 to 1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film’s shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15-24 days for systems stored at fridge or room temperature conditions respectively

Aroma delivery from spray dried coffee containing pressurised internalised gas

A non-chemical, ingredient free method of enhancing aroma delivery during the preparation of instant coffee is presented. The approach detailed introduces a method for entrapping high pressure internalised gas within the pores of spray dried soluble coffee by cycling of both pressure and temperature. The headspace delivery of volatile aroma compounds during powder hydration was tracked by an atmospheric pressure chemical ionisationquadrupole mass spectrometer, with a modified ion source. The release of pressurised gas on hydration caused a burst of volatile aroma compounds into the headspace, which was both faster (77%) and more intense (60%) than could be achieved using standard instant coffee or through the use of chemical effervescent agents alone (sodium hydrogen carbonate and citric acid). In addition, the process of natural gasification selectively accelerated the delivery of individual aroma compounds, with the time to maximum headspace intensity being reduced for both 2,3 butanedione and acetaldehyde. © 2012 Elsevier Ltd

Effect of sweeteners and carbonation on aroma partitioning and release in beverage systems

The effect of monosaccharides (glucose, fructose and galactose) and disaccharides (sucrose and lactose) at 10, 20 and 30 % w/v on the in-vitro aroma partitioning of C - C aldehydes and ethyl esters, as well as limonene (concentration of aroma compounds at 1 μg mL ), was studied using atmospheric pressure chemical ionisation-mass spectrometry. An increase in sugar concentration from 0 to 30 % w/v resulted in a significant increase in partitioning under static headspace conditions for the majority of the compounds (p  0.05). The complexity of the system was increased to model a soft drink design - comprising water, sucrose (10, 20 and 30 % w/v), acid (0.15 % w/v), carbonation (∼7.2 g/L CO ) and aroma compounds representative of an apple style flavouring, namely ethyl butanoate and hexanal (10 μg mL each). Although the addition of sucrose had no significant in-vivo effect, carbonation significantly decreased breath-by-breath (in-vivo) aroma delivery (p  0.05). [Abstract copyright: Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.

The role of sodium chloride in the sensory and physico-chemical properties of sweet biscuits

© 2021 Salt is included in many foods which consumers do not regard as salty. This “hidden-salt” may offer functional benefits but is often overlooked in sodium reduction strategies. This study investigated its role in shortbread-like sweet biscuits (1.05 g NaCl/100 g). Sensory tests revealed significant flavour and texture differences after a salt reduction of 33% (0.86 g/ 100 g). This was explained by differences in the partitioning of hydrophobic aroma compounds into the headspace and a significant impact on structure. Texture analysis and X-ray-µCT measurements revealed a reduced hardness with larger and more air cells in salt-reduced biscuits. It is suggested that salt impacts on cereal proteins by altering their aggregation around flour particles and at bubble walls and that slower water loss occurs in salted matrices during baking. Hence, this study revealed the key properties significantly affected by salt reduction and proposes an explanation which will help to develop a targeted “hidden-salt” reduction strategy

COMPUTER-CONTROLLED GAS CHROMATOGRAPH CAPABLE OF ''REAL-TIME'' READOUT OF HIGH-PRECISION DATA.

A gas chromatograph has been assembled which provides computer control of sample injection, column temperature, and flow rate, plus direct computer readout of inlet pressure, mass flow rate, and detector response. Data processing yields, in real-time, a standard deviation of less than 0.05% in retention time, which is comparable to previous results obtained using an off-line computer. However, corrected retention volumes determined in real-time had a standard deviation of about 0.4% which reflected primarily the uncertainty in flow measurement

Stability of Lactobacillus rhamnosus GG incorporated in edible films: impact of anionic biopolymers and whey protein concentrate

The incorporation of probiotics and bioactive compounds, via plasticised thin-layered hydrocolloids, within food products has recently shown potential to functionalise and improve the health credentials of processed food. In this study, choice of polymer and the inclusion of whey protein isolate was evaluated for their ability to stabalise live probiotic organisms. Edible films based on low (LSA) and high (HSA) viscosity sodium alginate, low esterified amidated pectin (PEC), kappa-carrageenan/locust bean gum (κ-CAR/LBG) and gelatine (GEL) in the presence or absence of whey protein concentrate (WPC) were shown to be feasible carriers for the delivery of L. rhamnosus GG. Losses of L. rhamnosus GG throughout the drying process ranged from 0.87 to 3.06 log CFU/g for the systems without WPC, losses were significantly reduced to 0 to 1.17 log CFU/g in the presence of WPC. Storage stability (over 25d) of L. rhamnosus GG at both tested temperatures (4 and 25°C), in descending order, was κ-CAR/LBG>HSA>GEL>LSA=PEC. In addition, supplementation of film forming agents with WPC led to a 1.8- to 6.5-fold increase in shelf-life at 4°C (calculated on the WHO/FAO minimum requirements of 6 logCFU/g), and 1.6 to 4.3-fold increase at 25°C. Furthermore probiotic films based on HSA/WPC and κ-CAR/LBG/WPC blends had both acceptable mechanical and barrier properties

ICAR: endoscopic skull‐base surgery

n/