Optimising the hygiene of a liquid feeding system to improve the quality of liquid feed for pigs.

Poor feeding system hygiene may contribute to uncontrolled spontaneous fermentation in liquid pig feed and its associated undesirable effects. This study aimed to determine the effects of an intensive sanitisation programme in a grow-finisher liquid feeding system by monitoring microbiological and physico-chemical parameters of liquid feed and microbial colonisation of the feeding system surfaces. The sanitisation programme involved a combination of physical and chemical cleaning between batches of grow-finisher pigs, combined with nightly rinsing of the system with an organic acid blend. Improved hygiene of the internal surfaces of the mixing tank and feed pipeline, particularly until week 5 post-cleaning, was evidenced by reduced counts of lactic acid bacteria, total aerobes, Enterobacteriaceae, yeasts and moulds and decreased adenosine triphosphate concentrations. Enterobacteriaceae and moulds remained undetectable on pipeline surfaces for 10 weeks. Scanning electron microscopy of the feed pipelines confirmed these findings. Conversely, the impact on liquid feed microbiology was minimal and short-lived. However, acetic acid, ethanol and biogenic amine concentrations decreased in the feed post-cleaning and no gross energy losses were observed. Therefore, by controlling surface microbial communities on liquid feeding systems via implementation of the sanitisation programme developed in the current study, on-farm liquid feed quality should be improved.

Effect of heat treatment on the digestion behavior of pea and rice protein dispersions and their blends, studied using the semi-dynamic INFOGEST digestion method.

In the present study, the structuring and breakdown of a 5% protein dispersion prepared with commercial fractions of pea and rice isolates (PPI and RPI, respectively) were monitored by in vitro digestion. These proteins were blended in a 2 : 1 ratio of pea and rice, respectively, as this would deliver a high amino acid score. The effect of heating at 90 °C for 15 min on the digestion behavior was evaluated not only for the blend, but also for the respective protein isolate fractions, using the INFOGEST international consensus, semi-dynamic in vitro gastric model. Digesta were characterized by gel electrophoresis, light scattering, confocal laser scanning microscopy and size exclusion HPLC. Heating increased the solubility of PPI from 15.7% to 26.6% at pH 7.4. RPI showed low solubility (a maximum of 2.6% at pH 2), regardless of the treatment. Confocal microscopy observations evidenced major differences in the aggregates formed during digestion, with larger aggregates for heated PPI. While the unheated pea protein dispersions precipitated near the isoelectric pH, the heated counterpart formed macro-aggregates under the same conditions. In the case of RPI, there were no differences in structuring behaviour between unheated and heat treated reconstituted powder, due to their low solubility. Rice prolamins showed resistance to hydrolysis by pepsin and pancreatic enzymes. In the heated blend, macro-aggregates formed, but with a smaller size compared to heated pea protein alone, suggesting that pea protein aggregation was hindered by the presence of rice proteins. These results demonstrate how the composition of protein isolates can affect their in vitro digestion. However, pre-treatment of plant protein blends, such as heating, can modulate the rate and mechanism of digestion.

Raman spectroscopy: A rapid method to assess the effects of pasture feeding on the nutritional quality of butter.

The animal diet is a critical variable affecting the composition and functionality of dairy products. As "Grass-Fed" labeling becomes more prominent on the market, rapid and label-free methods for verification of feeding systems are required. This work proposes the use of Raman spectroscopy to study the effects of 3 different experimental cow feeding systems-perennial ryegrass pasture, perennial ryegrass with white clover pasture, and an indoor total mixed ration diet (TMR)-on the nutritional quality of sweet cream butter. The results demonstrate that Raman spectroscopy coupled with multivariate analysis is a promising approach to distinguish butter derived from pasture or conventional TMR feeding systems. A Pearson correlation analysis confirmed high positive correlations between the spectral bin at 1,657 cm-1, ascribed to the stretching vibrations of C=C bonds, and concentrations of α-linolenic acid and conjugated linolenic acid (CLA) in butter, and in general with the concentration of n-3 and n-3+CLA fatty acids and polyunsaturated fatty acids in the samples. The yellow color indicative of the presence of carotenoids in butter, which has previously been suggested as a biomarker of pasture or "Grass-Fed" feeding, was also positively correlated with the data obtained from the Raman spectra. Raman spectroscopy could also be used to accurately predict indicators of the nutritional quality of butter, such as the thrombogenic index, which showed a strong negative correlation with the spectral bin at 3,023 cm-1.

Structural and physicochemical characterization of thermoplastic corn starch films containing microalgae.

This work provides an in-depth analysis on how the addition of different microalgae species (Nannochloropsis, Spirulina and Scenedesmus) affected the structural and physicochemical properties of thermoplastic corn starch biocomposites. Structural characterization was conducted by combined SAXS/WAXS experiments and it was correlated with mechanical and barrier properties of the biocomposites. A water vapour permeability drop of ca. 54% was observed upon addition of the different microalgae species. The oxygen permeability and the mechanical properties of biocomposites containing Spirulina or Scenedesmus were not improved since the presence of microalgae hindered the re-arrangement and packing of the lamellar structure of starch polymeric chains, according to the SAXS results. Nannochloropsis caused a great reduction of the matrix rigidity and, the oxygen permeability was also improved. Therefore, all of these features make the Nannochloropsis biocomposites an alternative to generate biodegradable food packaging materials with the additional advantage that they can be easily scaled-up.