Flavor challenges in extruded plant-based meat alternatives: A review

Demand for plant-based meat alternatives has increased in recent years due to concerns about health, ethics, the environment, and animal welfare. Nevertheless, the market share of plant-based meat alternatives must increase significantly if they are to support sustainable food production and consumption. Flavor is an important limiting factor of the acceptability and marketability of plant-based meat alternatives. Undesirable chemosensory perceptions, such as a beany flavor, bitter taste, and astringency, are often associated with plant proteins and products that use them. This study reviewed 276 articles to answer the following five research questions: (1) What are the volatile and nonvolatile compounds responsible for off-flavors? (2) What are the mechanisms by which these flavor compounds are generated? (3) What is the influence of thermal extrusion cooking (the primary structuring technique to transform plant proteins into fibrous products that resemble meat in texture) on the flavor characteristics of plant proteins? (4) What techniques are used in measuring the flavor properties of plant-based proteins and products? (5) What strategies can be used to reduce off-flavors and improve the sensory appeal of plant-based meat alternatives? This article comprehensively discusses, for the first time, the flavor issues of plant-based meat alternatives and the technologies available to improve flavor and, ultimately, acceptability.     

Survival of Listeria monocytogenes on sliced cooked sausage after treatment with pediocin AcH

A preparation with pediocin AcH bound to its heat-killed producer cells Lactobacillus plantarum WHE 92 (starter culture ALC01, Wisby, Denmark) by adjusting the pH of the preparation to 6.0 was studied for its effects against Listeria monocytogenes ATCC 7644 and (spoilage) lactic acid bacteria on sliced cooked sausage. The pediocin AcH preparation or 0.9% (w/w) NaCl dilution (as a control) were randomly distributed dropwise on the surface of the slices. Treated slices were vacuum-packed and stored at 6 degrees C. Microbiological analysis and determination of pH values were performed after 3, 6, 9, 14 and 21 days of storage. Flavour of the sausages was evaluated after 7 and 11 days of storage. The pediocin preparation had effect (p > 0.05) neither on the growth of lactic acid bacteria, on the pH value nor on the flavour of vacuum-packed sliced sausage during 21 days of storage compared to control. However, during 6 days of storage, the number of L. monocytogenes decreased from the initial level of 2.7 log cfu/g sausage to < 2 log cfu/g, while on the control sausages the number of L. monocytogenes remained at the inoculated level. The numbers of L. monocytogenes remained at those levels to the end of storage period (21 days). However, the treated samples were determined to be Listeria positive, which indicates that the pediocin preparation was not efficient enough to kill all L. monocytogenes.     

Photovoltaic properties of PSi impregnated with eumelanin

A bulk heterojunction of porous silicon and eumelanin, where the columnar pores of porous silicon are filled with eumelanin, is proposed as a new organic-inorganic hybrid material for photovoltaic applications. The addition of eumelanin, whose absorption in the near infrared region is significantly higher than porous silicon, should greatly enhance the light absorption capabilities of the empty porous silicon matrix, which are very low in the low energy side of the visible spectral range (from about 600 nm downwards). The experimental results show that indeed the photocarrier collection efficiency at longer wavelengths in eumelanin-impregnated samples is clearly higher with respect to empty porous silicon matrices.     

Folate in oats and its milling fractions

Total folate content in oat varieties from three harvesting years (2006-2008), and in oats milling fractions, was determined using microbiological assay. Furthermore, folate vitamer distribution in milling fractions were examined with the UPLC method, which was taken in use and validated. The total folate content of the cultivars varied moderately within each year. The average content in the 2008 samples was 685ng/gdm. The UPLC method proved fast and sensitive for determining seven folate monoglutamates in cereal samples. Folate content in fractions, which are normally discarded, such as flour from oat cutting and flaking, were 1.5- to 2.5-fold higher than in native grain. The main folate vitamers found in the oat fractions were 5-CH(3)-H(4)folate, 5-HCO-H(4)folate, and 5,10-CH(+)-H(4)folate. The UPLC results more closely matched the microbiological results compared to those that are usually achieved with HPLC methods. This study illustrates that oats and, especially, by-products of milling are good sources of folate.     

Plasma Exosome Profile in ST-Elevation Myocardial Infarction Patients with and without Out-of-Hospital Cardiac Arrest

The identification of new biomarkers allowing an early and more accurate characterization of patients with ST-segment elevation myocardial infarction (STEMI) is still needed, and exosomes represent an attractive diagnostic tool in this context. However, the characterization of their protein cargo in relation to cardiovascular clinical manifestation is still lacking. To this end, 35 STEMI patients (17 experiencing resuscitated out-of-hospital cardiac arrest (OHCA-STEMI) and 18 uncomplicated) and 32 patients with chronic coronary syndrome (CCS) were enrolled. Plasma exosomes were characterized by the nanoparticle tracking analysis and Western blotting. Exosomes from STEMI patients displayed a higher concentration and size and a greater expression of platelet (GPIIb) and vascular endothelial (VE-cadherin) markers, but a similar amount of cardiac troponin compared to CCS. In addition, a difference in exosome expression of acute-phase proteins (ceruloplasmin, transthyretin and fibronectin) between STEMI and CCS patients was found. GPIIb and brain-associated marker PLP1 accurately discriminated between OHCA and uncomplicated STEMI. In conclusion, the exosome profile of STEMI patients has peculiar features that differentiate it from that of CCS patients, reflecting the pathophysiological mechanisms involved in STEMI. Additionally, the exosome expression of brain- and platelet-specific markers might allow the identification of patients experiencing ischemic brain injury in STEMI.     

Polyether Cyclization Cascade Alterations in Response to Monensin Polyketide Synthase Mutations

The targeted manipulation of polyketide synthases has in recent years led to numerous new-to-nature polyketides. For type I polyketide synthases the response of post-polyketide synthases (PKS) processing enzymes onto the most frequently polyketide backbone manipulations is so far insufficiently studied. In particular, complex processes such as the polyether cyclisation in the biosynthesis of ionophores such as monensin pose interesting objects of research. We present here a study of the substrate promiscuity of the polyether cyclisation cascade enzymes in monensin biosynthesis in the conversion of redox derivatives of the nascent polyketide chain. LC-HRMS/MS²-based studies revealed a remarkable flexibility of the post-PKS enzymes. They acted on derivatized polyketide backbones based on the three possible polyketide redox states within two different modules and gave rise to an altered polyether structure. One of these monensin derivatives was isolated and characterized by 2D-NMR spectroscopy, crystallography, and bioactivity studies.     

Stereoselective Biocatalyzed Reductions of Ginger Active Components Recovered from Industrial Wastes

Ginger is among the most widespread and widely consumed traditional medicinal plants around the world. Its beneficial effects, which comprise e. g. anticancer and anti-inflammatory activities as well as gastrointestinal regulatory effects, are generally attributed to a family of non-volatile compounds characterized by an arylalkyl long-chained alcohol, diol, or ketone moiety. In this work, ginger active components have been successfully recovered from industrial waste biomass of fermented ginger. Moreover, their recovery has been combined with the first systematic study of the stereoselective reduction of gingerol-like compounds by isolated alcohol dehydrogenases (ADHs), obtaining the enantioenriched sec-alcohol derivatives via a sustainable biocatalytic path in up to >99 % conversions and >99 % enantiomeric/diastereomeric excesses.     

Dispersal of brown trout (Salmo trutta L.) fry in a low gradient stream - implications for egg stocking practices

Stocking of eggs is a common strategy to support declining or reintroduce extirpated salmonid populations. Data on how juveniles disperse from stocking points is crucial to be able to design efficient stocking programs. Detailed information of dispersal is limited for many salmonids, for example, brown trout. In this study, dispersal distance was measured at the end of the first growing season in a low gradient (0.7%) stream in Sweden where the trout population had been depleted. Eggs from 17 separate sets of parents were stocked as eyed eggs in March. During the following fall fry were sampled throughout the stream. The majority of the fry dispersed downstream and remained within a distance of 200 m from the stocking point with no difference between sizes of fry and the presence of a competing cohort or not. There was no dissimilarity in dispersal distances across offspring originating from different parents indicating absence of genetic influence. Our results suggest that, in streams similar to our study site, stocking points should be separated by approximately 330 m in order to avoid overlap in habitat use of fry from different stocking points and that the presence of competing cohorts, fry size and within population variability in dispersal can be neglected.