Characterization of Microbiological Quality of Whole and Gutted Baltic Herring

There is growing interest in Baltic herring (Clupea harengus membras) and other undervalued, small-sized fish species for human consumption. Gutting or filleting of small-sized fish is impractical; hence, the aim of this study was to explore the suitability of the whole (ungutted) herring for food use. The microbiological quality of commercially fished whole and gutted herring was analysed with culture-dependent methods combined with identification of bacterial isolates with MALDI-TOF Mass Spectrometry and culture-independent 16S rRNA gene amplicon sequencing. Whole and gutted herring had between 2.8 and 5.3 log(10) CFU g(−1) aerobic mesophilic and psychrotrophic bacteria and between 2.2 and 5.6 log(10) CFU g(−1) H₂S-producing bacteria. Enterobacteria counts remained low in all the analysed herring batches. The herring microbiota largely comprised the phyla Proteobacteria, Firmicutes, and Actinobacteria (71.7% to 95.0%). Shewanella, Pseudomonas, and Aeromonas were the most frequently isolated genera among the viable population; however, with the culture-independent approach, Shewanella followed by Psychrobacter were the most abundant genera. In some samples, a high relative abundance of the phylum Epsilonbacteraeota, represented by the genus Arcobacter, was detected. This study reports the bacterial diversity present in Baltic herring and shows that the microbiological quality was acceptable in all the analysed fish batches

Synergistic use of fermentation and extrusion processing to design plant protein-based sausages

The synergistic effect of lactic acid fermentation and high-moisture extrusion processing of pea protein on the microbiological and sensory properties of plant-based sausages was investigated. Plant-based sausages were formed by combining fermented pea protein concentrate (PPC) biomass with high-moisture extruded pea protein isolate (PPI). Pea protein concentrate (PPC) was fermented with Lactococcus lactis subsp. lactis and Lactiplantibacillus plantarum to improve the perceived structure, texture, and flavour (specifically via expression of glutamic acid which is connected to umami flavour) of plant-based sausages.The sausages were prepared by stuffing the mixture of extruded PPI and fermented PPC (addition level 70:30) inside vegetarian casings followed by steam cooking. After preparation and cooking of the sausages, a trained sensory panel evaluated the intensities of ten selected attributes defining the flavour, odour, colour, and texture. In addition, dry matter content, acidification, microbial quality, and glutamate contents were analysed.The results demonstrated that fermentation decreased the pea-like odour and improved the texture of the sausages. In addition, yeast-like odour and umami taste were observed. The study was able to demonstrate novel clean-label processing approaches by combined fermentation and extrusion to generate in-situ meat-like flavour and texture based on plant protein ingredients

Comparison of Whole and Gutted Baltic Herring as a Raw Material for Restructured Fish Product Produced by High-Moisture Extrusion Cooking

Interest in using undervalued forage fish for human consumption has recently increased due to its environmental benefits. However, feasible strategies to process the undervalued fish species to food use are limited. Therefore, this study investigated the possibility to utilise whole (ungutted) Baltic herring as a raw material for hybrid plant-fish meat analogues produced by high-moisture extrusion cooking. The sample properties were compared with ungutted Baltic herring. Produced meat analogues showed sufficiently high microbial quality, with spoilage microbes showing growth levels of under 1.4 log CFU/g. Whole fish and gutted fish extrudates showed uniform flavour- and odour-related sensory profiles. Colour values of the whole fish (L* 57.8) extrudates were similar to the values of gutted fish extrudates (L* 62.0). The whole and gutted fish extrudates had tensile strength in a cross-cut direction of 25.5 and 46.3 kPa, respectively. This correlated with the tearing force of the extrudates analysed by a trained sensory panel. Furthermore, a more explicit protein network was microscopically observed in gutted fish than in whole fish extrudates. The present study showed that high-moisture extrusion cooking enables the use of whole small-sized fish for human consumption

Utilisation of co-streams in the Norwegian food processing industry

Food losses occur throughout the entire food chain, from primary production via postharvest handling and storage, to food processing, distribution, retailing and consumption. Globally, food losses account for about one third of the total food produced for human consumption. The aim of this report was to map the production and utilisation of co-streams in the food processing industry in Norway and to discuss possibilities for alternative utilisation based on qualitative aspects of the co-streams, and current legislation. This report is produced by work package 3 in the CYCLE project (2013-2016), “Total utilisation of raw materials in the supply chain for food with a bio-economical perspective”. The CYCLE project aims to improve resource utilisation in the Norwegian food chain by developing sustainable eco-friendly bio-processes and novel technology, in close relationship with food industry partners. Inputs and outputs of organic materials were roughly mapped at selected food processing plants presenting three Norwegian food chains: 1) Vegetables and potatoes; 2) white and pelagic fish; and 3) poultry. Data was collected during plant visits in June 2013, and later checked by staff from the described plants. The report describes the qualitative properties of co-streams, and their current utilisation as feed, fertiliser and as substrate for bioenergy production. We also present relevant regulations in EU and Norway regarding processing and utilisation of co-streams, and discuss alternative utilisation. Altogether, the food processing plants had significant market shares in Norway within fresh potatoes (38%), lettuce (17%), poultry meat (24%) and white and pelagic fish, where export makes up a large proportion. Generally, a large proportion of the raw materials were utilised as food and feed. On average for all plants, 75% of the raw material was utilised in food products, 21% in feed products, 1% in fertiliser and bioenergy production and 3% was deposited in landfill. The plants used in average 8.6 tonnes of process water per tonne of food produced, but the amount varied considerably between the plants. Possible improvements in the utilisation of raw materials and co-streams include a higher degree of utilisation in food products, and developing new or improved feed components from co-streams with increased nutritional value. Due to the current high degree of utilisation in food and feed applications with high economic values, the potential for bioenergy and fertiliser production is limited to certain risk materials. Feed potatoes and vegetables and feathers, bones, blood, viscera and skin from fish or poultry have considerable potential for better utilisation for food or feed. Relevant processing methods for these co-streams are fractionation, hydrolysis, fermentation and drying

Comparison of enzymatic and pH shift methods to extract protein from whole Baltic herring (Clupea harengus membras) and roach (Rutilus rutilus)

This study aimed to establish the differences between enzymatically extracted hydrolysates and pH shifted protein isolates from whole Baltic herring and roach in terms of polypeptide patterns, functionality, sensory properties, microbial quality, yield, and composition. Alkaline extraction resulted in the highest yields, whereas the hydrolysates showed the highest protein contents. The hydrolysates showed higher protein solubility (86.0–88.5%) than the protein isolates (5.1–14.5%) as well as the higher foam capacity for Baltic herring. However, for roach, alkaline extracted protein isolates exhibited the highest foam capacity. All hydrolysates showed poor foam stability (0–13%) while the protein isolates showed notably higher stability (30–55%). The hydrolysates showed relatively low bitterness, whereas alkaline extracted roach proteins were perceived as bitter. This study demonstrated that it was possible to produce protein isolates and hydrolysates from whole fish with good microbial quality. However, both processes need to be optimised according to the food application and fish species.</p

Quality of Protein Isolates and Hydrolysates from Baltic Herring (Clupea harengus membras) and Roach (Rutilus rutilus) Produced by pH-Shift Processes and Enzymatic Hydrolysis

Fractionation is a potential way to valorize under-utilized fishes, but the quality of the resulting fractions is crucial in terms of their applicability. The aim of this work was to study the quality of protein isolates and hydrolysates extracted from roach (Rutilus rutilus) and Baltic herring (Clupea harengus membras) using either pH shift or enzymatic hydrolysis. The amino acid composition of protein isolates and hydrolysates mostly complied with the nutritional requirements for adults, but protein isolates produced using pH shift showed higher essential to non-essential amino acid ratios compared with enzymatically produced hydrolysates, 0.84-0.85 vs. 0.65-0.70, respectively. Enzymatically produced protein hydrolysates had a lower total lipid content, lower proportion of phospholipids, and exhibited lower degrees of protein and lipid oxidation compared with pH-shift-produced isolates. These findings suggest enzymatic hydrolysis to be more promising from a lipid oxidation perspective while the pH-shift method ranked higher from a nutrient perspective. However, due to the different applications of protein isolates and hydrolysates produced using pH shift or enzymatic hydrolysis, respectively, the further optimization of both studied methods is recommended

Natural Antimicrobials from Cloudberry (Rubus chamaemorus) Seeds by Sanding and Hydrothermal Extraction

We have developed an organic solvent-free process to enrich natural antimicrobials from the important Nordic Rubus berry species, especially from cloudberry. The process utilizes industrial berry byproducts as raw-material, and it is based on seed sanding technology and water-based extraction. The extracts showed strong antimicrobial activity against Gram-positive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA). A concentration of 5 mg/mL totally eliminated these bacteria in 24 h. Effects against Gram-negative bacteria were modest. Polyphenol analysis of the hydrothermal extracts showed that the antimicrobial activity is correlated to ellagitannins, mainly dimeric sanguiin H-6 and sanguiin H-10 isomers. Sanguiin H-10 is not commonly found in intact cloudberry seeds, but it is formed from the dimeric and trimeric ellagitannins, during the extraction. Surprisingly hydrothermal extracts had no or minor effects on beneficial bacteria, Lactobacillus rhamnosus. This interesting finding might offer an application potential in controlling skin microbial pathogens, for example, in wound healing.</p

Kaiken takana on laadukas raaka-aine – Silakan laadun mittausmenetelmät

Kalatalouden innovaatio-ohjelma Blue Products keskittyy kotimaisen kalan arvon lisäämiseen kehittämällä alihyödynnettyjen kalojen, kuten silakan ja särkikalojen käyttöä elintarvikkeissa ja uusissa, innovatiivisissa korkean lisäarvon erikoistuotteissa. Kuluttajien kiinnostus silakkaa ja särkikaloja kohtaan ympäristöystävällisenä ja terveellisenä ruokana on viime aikoina kasvanut, mutta toisaalta samaan aikaan yrityskentältä ja kuluttajilta on tullut viestiä silakan laadun vaihtelusta ja liian heikosta säilyvyydestä. Sekä perinteistä ruokakäyttöä että innovatiivisempia tuotteita varten kalan laadun onkin oltava erinomainen. Jotta silakan laatua pystytään parantamaan, pitää laatu pystyä mittaamaan numeerisesti kalastusalukselta kauppaan. Tässä raportissa arvioidaan erilaisten mittausmenetelmien soveltuvuutta silakan laadun määrittämiseksi kalaketjun eri vaiheissa ja tarvetta uusille pikamenetelmille laadun mittaamiseksi.Kuluttajalle laatu näyttäytyy aistittavana laatuna. Kalojen aistinvaraisen laadun tutkimuksessa voidaan käyttää monenlaisia menetelmiä, mutta kalaketjun käyttöön tarvitaan helposti omaksuttava ja mielellään älylaitteessa toimiva yksinkertainen numeerinen mittari. Tällaiseksi voisi soveltua silakalle kehitetty laatuindeksiin perustuva älypuhelinsovellus, joka mukailee ”How fresh is your fish”-sovellusta. Tämän tuomiseksi käytäntöön tarvitaan yhteistyökumppaniksi ohjelmistoyritys. Aistittavan laadun taustatekijät ovat joukko kemiallisia, biokemiallisia, fysikaalisia ja mikrobiologisia ilmiöitä, joiden mittaamiseen löytyy lukuisia menetelmiä. Lupaavilta kalan laadunvalvontaan ja tuoreuden arviointiin prosessoinnissa ja kaupassa vaikuttavat kaupalliset pikamenetelmät kuten ”Freshness checker” ja ”PRECICE® Freshness Assay Kit”, sekä pakattujen tuotteiden kohdalla erilaiset värimuutokseen perustuvat kemosensitiiviset sensorit, jotka viestivät kalan laadusta sekä kuljetuksen että säilytyksen aikana. Kalan sähköisten ominaisuuksien muutoksiin perustuvat Torrymeter sekä Fischtester VI ovat edelleen käyttökelpoisia, kaupallisesti saatavia, koko ketjun seurantaan soveltuvia kalan tuoreusmittareita, mutta ne ovat epäherkkiä ja alttiita erilaisille virhemittauksille. Sähkökemiallinen impedanssispektrosopia (EIS) antaa kalan koostumuksesta tarkempaa informaatiota. Tämän menetelmän mahdollisuuksia silakan laadun mittaamiseen tullaan testaamaan Blue Products -ohjelman jatkotutkimuksissa. Erilaiset kuvantamistekniikat, kuten hyperspektrikuvantaminen, tarjoavat mielenkiintoisia uusia mahdollisuuksia kalan laadun määrittämiseksi ja esimerkiksi kalansaaliin lajitteluun laadun perusteella. Kuvantamistekniikka on vielä nykyisellään melko kallista, mutta toisaalta kuvantamismenetelmät ovat jo vakiinnuttaneet asemansa laajasti teollisuuden eri aloilla ja elintarviketeollisuudessa laaduntarkkailussa.</p

Case Nortura/Norilia.Improving the utilisation of co-streams in poultry processing

Industrialised chicken production is far from organic agriculture prinicples. Still of interest is a more sustainable utilisation of by-products, e.g. hydrolysation of feathers for proteins, or extraction of food grade oil from chicken bones. Such approaches were studied in the bioeconomy-project "CYCLE" (2013-2017)