Caviar and fish roe substitutes: Current status of their nutritive value, bio-chemical diversity, authenticity and quality control methods with future perspectives

Valorisation of sea urchin (Paracentrotus lividus) gonads through canning

Fresh sea urchin (Paracentrotus lividus) gonads are a delicacy with short seasonal availability, very often heterogeneous in size and intrinsic characteristics. This study aimed to valorise this resource through the preparation of canned products (with/without Porphyra spp.) and evaluate their physicochemical and sensory quality (3-12 months). Canning contributed to a decrease in protein, K and most carotenoids contents; and a concentration of lipids, ash, Na and Se levels. A simulated 12-month ageing led to decrease the protein and β-carotene contents; and the Na and lutein levels concentration. The macroalgae addition resulted in an orange, darker and less soft product, with higher carbohydrates, Na, Se and carotenoids contents. A 25 g-dose contributes to significant daily intakes of protein (8-9%), EPA+DHA (47-53%), I (35-62%) and Se (30-47%). The products were commercially stable/sterile and had good sensory acceptance. Overall, canning constitutes a strategy to provide a nutritionally balanced product available all year-round.

Agriculture and environmental management through nanotechnology: Eco-friendly nanomaterial synthesis for soil-plant systems, food safety, and sustainability

Through the advancement of nanotechnology, agricultural and food systems are undergoing strategic enhancements, offering innovative solutions to complex problems. This scholarly essay thoroughly examines nanotechnological innovations and their implications within these critical industries. Traditional practices are undergoing radical transformation as nanomaterials emerge as novel agents in roles traditionally filled by fertilizers, pesticides, and biosensors. Micronutrient management and preservation techniques are further enhanced, indicating a shift towards more nutrient-dense and longevity-oriented food production. Nanoparticles (NPs), with their unique physicochemical properties, such as an extraordinary surface-to-volume ratio, find applications in healthcare, diagnostics, agriculture, and other fields. However, concerns about their potential overuse and bioaccumulation raise unanswered questions about their health effects. Molecule-to-molecule interactions and physicochemical dynamics create pathways through which nanoparticles cause toxicity. The combination of nanotechnology and environmental sustainability principles leads to the examination of green nanoparticle synthesis. The discourse extends to how nanomaterials penetrate biological systems, their applications, toxicological effects, and dissemination routes. Additionally, this examination delves into the ecological consequences of nanomaterial contamination in natural ecosystems. Employing robust risk assessment methodologies, including the risk allocation framework, is recommended to address potential dangers associated with nanotechnology integration. Establishing standardized, universally accepted guidelines for evaluating nanomaterial toxicity and protocols for nano-waste disposal is urged to ensure responsible stewardship of this transformative technology. In conclusion, the article summarizes global trends, persistent challenges, and emerging regulatory strategies shaping nanotechnology in agriculture and food science. Sustained, in-depth research is crucial to fully benefit from nanotechnology prospects for sustainable agriculture and food systems.

Changes in the chemical properties and metabolite profiling of fish sauce prepared from underutilized large yellow croaker roes during fermentation at different temperatures

Fish sauce is a popular aquatic condiment with unique flavor. In this study, the changes in the chemical properties and metabolite profiling of fish sauce from large yellow croaker roes during fermentation at different temperatures were revealed. The results found that the contents of total acid, amino acid nitrogen, total soluble nitrogen and soluble salt-free solids of fish sauce fermented at 40 °C were higher than those in other temperatures groups (25 °C and 32 °C), while the contents of total volatile basic nitrogen were lower than other temperatures. Therefore, 40 °C was the ideal fermentation temperature for fish sauce. The metabolomics analysis showed that organic acids, amino acids, nucleotide, and lipid compounds were found to participate in the biosynthesis pathway. Compared to 25 °C and 32 °C, fermented at 40 °C could increase the abundance of metabolic substances in the fish sauce, such as sugar alcohols, L-Citrulline, L-Aspartic acid, L-Cysteine, Glutathione, and L-Arginine. These results provide a theoretical basis for the production of high-quality fish sauce and the high-value utilization of fish roes.

Ultrasonic imaging as a means of monitoring gonadal development in lumpfish (Cyclopterus lumpus)

The commercial farming of juvenile lumpfish requires monitoring of gonadal development to achieve synchronized production. Conventional methods such as gonadosomatic index (GSI), sex hormone analyses, gonadal histology, endoscopy, and gene expression analyses are costly, invasive, and often involve sacrificing the fish. We assessed the efficiency of ultrasound as a non-invasive method for monitoring gonadal development in lumpfish. Based on ultrasound observations, we categorized the fish into six stages; F0 to F5 for females and M0 to M5 for males, that represented maturity levels from immature to spent. Importantly, the ultrasound gonadal stages aligned with histological gonadal stages. Additionally, ultrasound stages aligned with profiles of GSI, testosterone (T), 11-ketotestosterone, and 17β-estradiol throughout gonadal development including the spawning period. Moreover, these parameters exhibited significant positive correlations with each other reflecting their parallel trends during gonadal development. To minimize the frequency of ultrasound usage and fish handling, we established F3 and M3/M4 as arbitrary thresholds for identifying ripe females and males, respectively. By using these thresholds, the need for regular ultrasound monitoring could be reduced during most of the rearing period. Ultrasound proves to be useful and reliable for monitoring gonadal development in lumpfish, enabling synchronized production of juvenile fish.

Species Identification of Caviar Based on Multiple DNA Barcoding

This study aimed to explore the applicability of DNA barcoding for assessing the authenticity of caviar on the Chinese market. A set of universal COI primers and two sets of designed primers based on COI and D-loop genes were used to identify maternal species of samples from 21 batches of caviar. The results showed that the PCR products from three sets of primers had more than 98% similarity to the sequences in database. The COI gene could not distinguish sturgeons with closed genetic relationships, while D-loop gene could effectively improve the accuracy of DNA barcoding and was more suitable to the identification of interspecific sturgeon than the COI gene. The neighbor-joining dendrogram further confirmed the applicability and accuracy of COI and D-loop genes in identifying maternal relatives of caviar (Acipenser baerii/Acipenser gueldenstaedtii/Acipenser schrenckii/Huso dauricus/Huso huso). Despite the limitations of mitochondrial DNA in identifying hybrid sturgeon species, the presence of counterfeit caviar of non-sturgeon ingredients could be excluded. All the caviar samples were identified successfully as sturgeon species, but the mislabeling rate of species was 33.4%, indicating that there were illegal phenomena such as disorderly labeling, mislabeling, and adulteration on the market.

Identification of black sturgeon caviar pigment as eumelanin

Reported herein is the purification of the pigment of black sturgeon caviar and its unambiguous identification as a typical eumelanin by means of chemical degradation coupled with electron paramagnetic resonance (EPR) evidence. HPLC and LC-MS analysis of oxidative degradation mixtures revealed the formation of pyrrole-2,3,5-tricarboxylic acid (PTCA), a specific marker of eumelanin pigments, in yields compatible with a 6.5% w/w pigment content. EPR spectral features and parameters were in close agreement with those reported for a typical natural eumelanin such as Sepia melanin from squid ink. The identification for the first time of eumelanin in a fish roe is expected to provide a novel molecular basis for the valorization of black caviar and production wastes thereof in food chemistry and diet.

Estimation of Target Hazard Quotients and Potential Health Risks for Toxic Metals and Other Trace Elements by Consumption of Female Fish Gonads and Testicles

The aim of this study was to assess the risk to consumers associated with the intake of toxic metals and other trace elements in diets that include the female gonads, testicles, and muscles of four popular freshwater fish species in Poland—common bream (Abramis brama L.), European perch (Perca fluviatilis L.), common roach (Rutilus rutilus L.), and northern pike (Esox Lucius L.). The following methods were used to determine the elements: GF-AAS (Pb, Cd); CV-AAS (Hg); ICP-AES (Zn, Fe, Mn, Cu, Ni, Li, Cr, Al). The concentration of toxic elements (Hg, Cd, Pb) in the female gonads and testicles ranged from 0.004 ± 0.006 mg/kg (Cd) to 0.028 ± 0.018 mg/kg (Pb). Of the other elements, the lowest content was noted for Cr (0.122 ± 0.182 mg/kg) and the highest for Al (46.98 ± 31.89 mg/kg). The study confirmed that female gonads and testicles are a valuable source of essential trace elements (Zn, Fe). Considering the content of toxic elements, the raw material of female gonads and testicles posed no health risks (THQ < 1).

The Effect of Combined Superheated Steam Roasting and Smoking on the Quality Characteristic of Alaska Pollack (Gadus chalcogrammus) Roe

Alaska pollack roe (APR) is a protein source that is usually salted and fermented, containing a high salt content. Using a combination of superheated steam roasting and smoking, we developed a new low-salt ready-to-eat APR variant, whose quality characteristics we analyzed. The optimal conditions for roasting (216 °C for 4 min) and smoking (64 °C for 14 min) were obtained from sensorial attributes using response surface methodology. Under the optimal conditions, smoke-roasted APR had an overall acceptance (OA) score of 8.89. The combination of roasting and smoking significantly increased volatile basic nitrogen (VBN, 18.6%) and decreased the total bacterial count (TBC, 38.6%), while thiobarbituric acid reactive substances (TBARS) were not affected. Smoke-roasting APR also increased its nutritional content to 30% protein with 44% essential amino acids, and more than 40% DHA and EPA in 4.3% fat. During 30 days of storage, the OA, VBN, TBARS, and TBC values significantly changed with time and storage temperature (p < 0.05). The shelf life of the product was estimated to be 24 d. In conclusion, the combination of roasting and smoking APR could improve product quality and may be an alternative to diversify processed APR.