Changes in the free amino acids and the biogenic amine contents during lactic acid fermentation of different lupin species

The aim of the work was to evaluate the profile of free amino acids (FAA) as the possible precursors of biogenic amines (BAs) in different varieties and hybrid lines of Lupinus luteus and Lupinus angustifolius and its changes during fermentation. Lupins have high amounts of FAA, and therefore, significant contents of BAs by the action of bacterial amino acid decarboxylases can be formed. In view of this, the effect of three Pediococcus pentosaceus strains KTU05‐8, KTU05‐9 and KTU05‐10 on BA formation during lupin fermentation was studied. The formation of BAs was monitored during 48‐h fermentation at solid‐state conditions and compared with that in samples after submerged fermentation and in the control nonfermented samples. The lupin variety, fermentation conditions and the Pediococcus strain were found to have the significant effect on the FAA profile and BA contents in fermented lupin; the interaction between analysed factors was F(5.989) = 1755.321 (P < 0.0001) and F(5.660) = 130.736 (P < 0.0001), respectively. A weak correlation was found between amino acid His and histamine (r = 0.3709; P = 0.0005) and between Phe and phenylethylamine (r = 0.3914, P = 0.0002) in lupin samples, but the significant correlations between amino acid Tyr and tyramine and between Lys and cadaverine were not found. By optimising the fermentation technology, it is possible to increase the nutritional value and functionality of lupin.     

Modulation of the nutritional value of lupine wholemeal and protein isolates using submerged and solid‐state fermentation with Pediococcus pentosaceus strains

The influence of different factors (submerged and/or solid‐state fermentation, pediococci strain, lupine variety and protein isolation process) on the protein digestibility, total phenolic compounds (TPC) content and radical scavenging activity of Lupinus luteus and angustifolius wholemeal and protein isolates was evaluated. As safety factor, biogenic amines (Bas) formation was analysed. The Pediococcus pentosaceus strains No. 8, No. 9 and No. 10 are suitable starters for lupine wholemeal fermentation and both applied processes (fermentation and protein isolation) increase protein digestibility (by 10%). Higher TPC content in fermented wholemeal can be obtained, compare to isolates. In SMF isolates by 58.3%, 68.2%, 95.6%, 76.6%, lower content of phenylethylamine, putrescine, cadaverine and histamine, respectively was found. The highest protein digestibility and the lowest BAs content using submerged fermentation with pediococcus No. 8 in lupine variety Vilnius protein isolates can be obtained and this technology for high‐quality lupine proteins preparation can be recommended.     

Nutraceuticals in gummy candies form prepared from lacto‐fermented lupine protein concentrates,as high‐quality protein source,incorporated with Citrus paradise L. essential oil and xylitol

As an addition to a normal diet, the use of food enriched with functional compounds has become increasingly popular. Alternatively, functional ingredients can be incorporated into nutraceuticals in gummy candies (GC) form. This study aimed to adapt lacto‐fermented lupine protein concentrates, as high‐quality protein and genistein sources, with Citrus paradise essential oil (EO), an antimicrobial and bean taste masking agent, and xylitol, a low glycaemic index sweetener, for preparation of nutraceuticals in GC form. For GC preparation, submerged fermentation with Lactobacillus sakei lupine variety Vilniai protein concentrate was selected, which had the highest protein content (90.11%), protein digestibility (89.94%) and genistein content (30.93 μg g^?1) and the lowest trypsin inhibitors activity (19.40%), among the concentrates assessed. GC formulated with xylitol, ascorbic acid, grapefruit EO (up to 0.2%) and lupine protein concentrate (up to 13.0%) allowed obtaining products that exhibited a good texture, high overall acceptability and contained desirable functional compounds.     

Technology and characterisation of whole hemp seed beverages prepared from ultrasonicated and fermented whole seed paste

The aim of this study was to apply fermentation with Pediococcus acidilactici LUHS29, P. pentosaceus LUHS183, Lactobacillus casei LUHS210 and L. uvarum LUHS245 strains, as well as ultrasonication (US) for whole hemp (Cannabis sativa L.) seed paste (HSP) treatment and preparation of emulsions (HSE). Additionally, the biogenic amine (BA) content and antimicrobial properties of the prepared products were evaluated. It was found that US and fermentation reduced total bacteria count in HSP. The highest BA content was found in US-treated HSP (639.87 mg kg⁻¹). HSE_US, HSE_LUHS29, HSE_LUHS183, HSE_LUHS210 and HSE_LUHS245 samples showed lower ζ-potential. The highest overall acceptability (OA) was established for HSE_LUHS245, and correlations were established between the emotions induced by the different HSE products and OA. Pure LAB showed a broad variety of pathogen inhibition; however, the antimicrobial activity of HSP was very low, and HSE did not show any antimicrobial properties. Finally, treatment with selected LAB can be recommended for preparation of stable emulsions, and the most acceptable beverages can be obtained by using LUHS245 strain.     

Evaluation of the use of lactic acid bacteria and Thymus vulgaris essential oil on Suffolk and Ile de France lamb breed (MuscuIus gluteus) quality parameters

In the present study, Lactobacillus plantarum (LUHS135), Thymus vulgaris essential oil (0.1% v/v) and their combination were used to treat Suffolk and Ile de France lamb meat. Changes in the microbiological profile and physicochemical parameters of meat were evaluated after 24 h of treatment at 4 °C. Treatments resulted in significantly lower mould/yeast, total enterobacteria (by up to 45%) counts, water-holding capacity (by 21–63%) and cooking loss (by 17–35%) in all samples. Moisture content increased, on average, by 14.5% in the Suffolk meat. Polyunsaturated fatty acid content increased after all treatments. Treatments and breed significantly affected the content of malondialdehyde and some biogenic amines. Sensory analysis showed that raw lamb meat colour was more acceptable after all treatments, while the odour acceptability was ranked highest after combined treatment. These findings suggest that the applied treatments could be used to improve microbiological safety and some quality characteristics and to increase the PUFA content of lamb meat.     

Perspectives of lupine wholemeal protein and protein isolates biodegradation

Lupine (Lupinus angustifolius L.) protein (in wholemeal and protein isolates) was biodegraded using Pediococcus acidilactici in submerged and solid-state fermentation conditions. The changes in the molecular weight of lupine protein fractions, amino acid (AA) profile, biogenic amine formation, antimicrobial and antioxidant properties, and protein digestibility in vitro and in vivo (in Wistar rats) were evaluated. After biotreatment, lower molecular weight peptides (from 10 to 20 kDa) were established, and the free AA content increased. Biodegradation improved the antioxidant properties, modulated the antimicrobial properties, and led to higher in vitro and in vivo digestibility and functionality of the lupine in treated rats (significant increase in body weight of Wistar rats, and increased acetic acid concentration and lowered Escherichia coli count in the caecum). Overall, the biodegradation of lupine protein can transform the plant protein, producing enhanced functionality and bioavailable products.     

Facile One Step Formation and Screening of Tumor Spheroids Using Droplet‐Microarray Platform

Tumor spheroids or microtumors are important 3D in vitro tumor models that closely resemble a tumor's in vivo “microenvironment” compared to 2D cell culture. Microtumors are widely applied in the fields of fundamental cancer research, drug discovery, and precision medicine. In precision medicine tumor spheroids derived from patient tumor cells represent a promising system for drug sensitivity and resistance testing. Established and commonly used platforms for routine screenings of cell spheroids, based on microtiter plates of 96‐ and 384‐well formats, require relatively large numbers of cells and compounds, and often lead to the formation of multiple spheroids per well. In this study, an application of the Droplet Microarray platform, based on hydrophilic–superhydrophobic patterning, in combination with the method of hanging droplet, is demonstrated for the formation of highly miniaturized single‐spheroid‐microarrays. Formation of spheroids from several commonly used cancer cell lines in 100 nL droplets starting with as few as 150 cells per spheroid within 24–48 h is demonstrated. Established methodology carries a potential to be adopted for routine workflows of high‐throughput compound screening in 3D cancer spheroids or microtumors, which is crucial for the fields of fundamental cancer research, drug discovery, and precision medicine.