No abstract

In the present study, inclusion of mealworm (Tenebrio molitor L.) powder into bread doughs at 5 and 10% substitution level of soft wheat (Triticum aestivum L.) flour was tested to produce protein fortified breads. The addition of mealworm powder (MP) did not negatively affect the technological features of either doughs or breads. All the tested doughs showed the same leavening ability, whereas breads containing 5% MP showed the highest specific volume and the lowest firmness. An enrichment in protein content was observed in experimental breads where the highest values for this parameter were recorded in breads containing 10% MP. Breads fortified with 10% MP also exhibited a significant increase in the content of free amino acids, and especially in the following essential amino acids: tyrosine, methionine, isoleucine, and leucine. By contrast, no differences in nutritional quality of lipids were seen between fortified and control breads. Results of sensory analyses revealed that protein fortification of bread with MP significantly affected bread texture and overall liking, as well as crust colour, depending on the substitution level. Overall, proof of concept was provided for the inclusion of MP into bread doughs started with different leavening agents (sourdough and/or baker’s yeast), at 5 or 10% substitution level of soft wheat flour. Based on the Technology Readiness Level (TRL) scale, the proposed bread making technology can be situated at level 4 (validation in laboratory environment), thus suggesting that the production of breads with MP might easily be scaled up at industrial level. However, potential spoilage and safety issues that need to be further considered were highlighted.

No abstract

The well-recognized efficiency of Tenebrio molitor larvae to convert low quality organic matter into a nutritionally valuable biomass was exploited to manage solid wastes coming from the olive oil industry, which represent a severe environmental challenge in the Mediterranean area. Three organic pomace-enriched substrates (mixtures middlings/pomace 3:1, 1:1, and 1:3) were assessed, together with 100% organic wheat flour and 100% organic middlings as control feeds. A feeding substrate made up of 25% olive pomace and 75% wheat middlings appeared to be the best compromise between growth performance (larval and pupal weights, survival rate, development time) and nutritional properties of mealworm larvae. In fact, larvae fed the 3:1 feed showed the highest dry matter (DM) yield (38.05%), protein content (47.58% DM), and essential/non-essential amino acids ratio (1.16). Fat content (32.14% DM) and fatty acid composition were not significantly different than those of larvae fed more pomace-enriched feeds.

No abstract

No abstract

In the present research, bacterial diversity was studied during a 6-month feeding trial utilizing zebrafish (Danio rerio) fed Hermetia illucens reared on different substrates with an emphasis on fish gut bacterial diversity. A polyphasic approach based on viable counting, PCR-DGGE and metagenomic 16S rRNA gene amplicon target sequencing was applied. Two different H. illucens groups were reared on coffee by-products (C) or a mixture of vegetables (S). Viable counts showed a wide variability based on substrate. PCR-DGGE and Illumina sequencing allowed the major and minor bacterial taxa to be detected. Both samples of larvae and their frass reared on the S substrate showed the highest richness and evenness of bacterial communities, whereas zebrafish (ZHC) fed H. illucens reared on substrate C and zebrafish (ZHS) fed H. illucens reared on substrate S had the lowest bacterial richness and evenness. A stimulating effect of bioactive compounds from coffee by-products on the occurrence of Lactobacillaceae and Leuconostoccaceae in H. illucens reared on substrate C has been hypothesized. Zebrafish gut samples originating from the two feeding trials showed complex microbial patterns in which Actinobacteria and Alteromonadales were always detected, irrespective of the diet used. Enterobacteriaceae in fish guts were more abundant in ZHS than in ZHC, thus suggesting an influence of the bioactive compounds (chlorogenic and caffeic acids) in the substrate on Enterobacteriaceae in fish guts. ZHC showed a higher abundance of Clostridia than did ZHS, which was likely explained by stimulating activity on the bacteria in this class by the bioactive compounds contained in H. illucens reared on substrate C. An influence of the microbiota of H. illucens or insect-derived bioactive compounds on the gut microbiota of zebrafish has been suggested. The presence of bacteria consistently associated with zebrafish guts has been found irrespective of the diet, thus attesting to the likely stability of the core fish microbiota.

33Hákarl is produced by curing of the Greenland shark (Somniosus microcephalus) flesh, which before fermentation is 34 toxic due to the high content of trimethylamine (TMA) or trimethylamine N-oxide (TMAO). Despite its long history of 35 consumption, little knowledge is available on the microbial consortia involved in the fermentation of this fish. In the 36 present study, a polyphasic approach based on both culturing and DNA-based techniques was adopted to gain insight 37 into the microbial species present in ready-to-eat hákarl. To this aim, samples of ready-to-eat hákarl were subjected to 38 viable counting on different selective growth media. The DNA directly extracted from the samples was further 39 subjected to Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) and 16S amplicon-40 based sequencing. Moreover, the presence of Shiga toxin-producing Escherichia coli (STEC) and Pseudomonas 41 aeruginosa was assessed via qualitative real-time PCR assays. pH values measured in the analyzed samples ranged 42 from between 8.07±0.06 and 8.76±0.00. Viable counts revealed the presence of total mesophilic aerobes, lactic acid 43 bacteria and Pseudomonadaceae. Regarding bacteria, PCR-DGGE analysis highlighted the dominance of close relatives 44 of Tissierella creatinophila. For amplicon sequencing, the main operational taxonomic units (OTUs) shared among the 45 data set were Tissierella, Pseudomonas, Oceanobacillus, Abyssivirga and Lactococcus. The presence of Pseudomonas 46 in the analyzed samples supports the hypothesis of a possible role of this microorganism on the detoxification of shark 47 meat from TMAO or TMA during fermentation. Several minor OTUs (<1%) were also detected, including 48 Alkalibacterium, Staphylococcus, Proteiniclasticum, Acinetobacter, Erysipelothrix, Anaerobacillus, Ochrobactrum, 49 Listeria and Photobacterium. Analysis of the yeast and filamentous fungi community composition by PCR-DGGE 50 revealed the presence of close relatives of Candida tropicalis, C. 52 tenuissimum, Moristroma quercinum and Phoma/Epicoccum, and some of these species probably play key roles in the 53 development of the sensory qualities of the end product. Finally, qualitative real-time PCR assays revealed the absence 54 of STEC and Pseudomonas aeruginosa in all of the analyzed samples. 55 56