Physico-chemical Properties and Sensorial Appreciation of a New Fermented Probiotic Beverage Enriched with Pea and Rice Proteins.

OBJECTIVES: The purpose of this study was to evaluate the physico-chemical stability, the sensorial properties, and the microbial quality of a fermented beverage enriched with pea and rice proteins (PRF) during storage at 4 °C. To investigate the effect of the protein enrichment and fermentation, the PRF beverage quality was compared with non-fermented and non-enriched beverages. METHODS: The beverage was supplemented with a 50/50 mixture of pea and rice protein concentrate to 13% concentration. Following inoculation with 108 CFU/mL of lactic acid bacteria, it was incubated at 37 °C for 14 h. RESULTS: Results showed that the enrichment with protein induced an increase in pH, titratable acidity and viscosity of the PR products, while the fermentation led to a decrease of pH and viscosity. However, a significant increase of the viscosity of PRF from 39 to 57 cP was observed during the 143 days of storage (P ≤ 0.05). The PRF beverage contained significantly more peptides < 200 Da than the non-fermented one (PRNF) and these small peptides were also released during the storage. Despite the physico-chemical modifications, the sensorial properties of the PRF product were appreciated over the storage, particularly for the texture. Furthermore, the beverage maintained a high concentration of viable probiotics during the entire storage with 8.4 log colony form unit (CFU)/mL after 143 days. CONCLUSION: Applying probiotics and the mixture of rice and pea proteins in the fermented beverage can enhance nutritional and nutraceutical value of the product.

Effect of Physical and Enzymatic Pre-Treatment on the Nutritional and Functional Properties of Fermented Beverages Enriched with Cricket Proteins.

The aim of this study was to evaluate the effects of γ-irradiation (IR), ultrasound (US), and combined treatments of ultrasound followed by γ-irradiation (US-IR), ultrasound followed by enzymatic hydrolysis with and without centrifugation (US-E and US-EWC, respectively), and ultrasound followed by γ-irradiation and enzymatic hydrolysis (US-IRE), on the digestibility and the nutritional value of fermented beverages containing probiotics. Results showed that US (20 min), IR (3 kGy) and US-IR (tUS = 20 min, dose = 3 kGy) treatments raised protein solubility from 11.5 to 21.5, 24.3 and 29.9%, respectively. According to our results, these treatments were accompanied by the increased amount of total sulfhydryl groups, surface hydrophobicity and changes to the secondary structure of the proteins measured by Fourier-transform infrared spectroscopy (FTIR). Fermented probiotic beverages, non-enriched (C) and enriched with untreated (Cr) or treated cricket protein with combined treatments were also evaluated for their in vitro protein digestibility. Results showed that the soluble fraction of US-IRE fermented beverage had the highest digestibility (94%) as compared to the whole fermented tested beverages. The peptides profile demonstrated that US-IRE had a low proportion of high molecular weight (MW) peptides (0.7%) and the highest proportion of low MW peptides by over 80% as compared to the other treatments.

In vitro protein digestibility and physico-chemical properties of lactic acid bacteria fermented beverages enriched with plant proteins.

The objective of this study was to develop probiotic beverages, enriched with plant proteins, with high nutritional value. A rice-based beverage fermented with a specific probiotic formulation comprised Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R and Lactobacillus rhamnosus CLR2 has been enriched with a combination of pea and rice proteins (PR) or pea and hemp proteins (PH) at 13 and 11% total protein, respectively. These protein associations have been selected because their amino acid ratio was >1, as recommended by the FAO. The beverage enriched with protein significantly increased its viscosity by more than 10 times thanks to the enrichment, while the fermentation reduced it by 50% for PR and 20% for PH. In vitro protein digestibility results showed that the protein enrichment and the fermentation treatment significantly increased digestibility values of the beverages with value of 72.7% for fermented PR beverage and 61.4% for unenriched fermented control beverage (p ≤ 0.05). Peptide profiles of PR and PH enriched beverages indicated that the fermentation led to a reduced level of high molecular weight (HMW) peptides of about 60% and an increase of low molecular weight (LMW) peptides by over 50%. Therefore, both the fermentation and the enrichment in protein increased the nutritional value of the rice-based beverages. PRACTICAL APPLICATION: Good quality of probiotics formulation and high-protein products are in increasing demand and plant proteins as an alternative of animal protein are popular. This study has permit to develop rice-based commercial probiotic beverages enriched in a combination of pea and rice or pea and hemp proteins in order to obtain a complete protein in terms of amino acids composition. The lactic acid fermentation and the enrichment with a plant protein combination led to a better protein digestibility of beverage.

Protein quality of a probiotic beverage enriched with pea and rice protein.

The aim of this study was to evaluate the effect of the fermentation of a probiotic beverage enriched with pea and rice proteins (PRF) on its protein quality. The protein quality was determined as the protein efficiency ratio (PER), net protein ratio (NPR), and the apparent (AD) and the true digestibility (TD) evaluated in vivo. The probiotic beverage was incorporated to a rat diet at a final concentration of 10% protein, for the evaluation of the PER, the NPR, the AD, and the TD. The protein digestibility amino acid score was also calculated. Results showed that the fermentation of beverage enriched with PRF had no effect on the TD but significantly increased the PER and the NPR (P ≤ 0.05) from 1.88 to 2.32 and from 1.66 to 2.30, respectively. Thus, the fermentation increased the protein quality of the PRF probiotic beverage. In addition, to determine if the beverage constitute in a good carrier matrix for the probiotics, the level of alive probiotics in the feces was evaluated and showed a concentration of 7.4 log CFU/g. PRACTICAL APPLICATION: Plant proteins are often of lower quality compared to animal proteins. Lactic acid fermentation of pea and rice protein has allowed to reach the same protein quality as casein. A plant-based fermented beverage with high protein quality and enriched with probiotics was developed.