Browsing by Author "Vaz-Pires, Paulo"
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- Freshness assessment and shelf-life prediction for Seriola dumerili from aquaculture based on the quality index methodPublication . Freitas, Jorge; Vaz-Pires, Paulo; Câmara, José S.Fish and fish-based products are easily perishable foods due to different factors, including fragile organization, abundant endo-enzymes, psychrophilic bacteria, and impact of pre-harvest operations, that contribute to reducing its value. Therefore, a timely effective method for fish freshness and shelf-life evaluation is important. In this context, this study aimed to develop a sensory scheme based on the Quality Index Method (QIM) (sensory table and point system) for freshness monitorization and shelf-life prediction for Seriola dumerili from aquaculture in Madeira Island. Evaluation of appearance, texture, eyes, and gills was performed during 20 days of storage on ice (0 ± 1 ◦C). The shelf-life prediction was supported by the analysis of microorganisms (total viable colonies, TVC, counts), texture (Torrymeter), and production of trimethylamine (TMA), evaluated by HS-SPME–GC–MS and validated according to Association of Official Analytical Chemists AOAC guidelines. The result is a QIM scheme with 25 demerit points, where zero indicates total freshness. From the integration of sensory analysis, microbial growth at the time of rejection (TVC, 108 cfu/cm2 and H2S producers, 107 cfu/cm2 ), texture (Torrymeter value < 8), and TMA analyses (>12.5 mg/100 g), shelf-life was estimated as 12 days (±0.5 days). The obtained results show the high-throughput potential of the developed method for fish freshness assessment and shelf-life prediction. This QIM scheme is a secure way to measure quality and provide users with a reliable standardized fish freshness measure.
- From aquaculture production to consumption: freshness, safety, traceability and authentication, the four pillars of qualityPublication . Freitas, Jorge; Vaz-Pires, Paulo; Câmara, José S.Farmed aquatic products are among the most widely traded commodities and one of the sectors with the fastest growth in the last years. However, aquaculture is still affected by negative connotations in comparison with other agroindustry sectors. Markets, consumer preferences and concerns about food safety and sustainability are influencing the growth of the sector and are forcing the implementation of quality management systems. Modern management systems help to minimize the environmental impacts and the distribution of unsafe or poor-quality products, thereby reducing the potential for bad image, liability and recalls. This article presents a compre hensive overview of the status, relevance, and impact of the quality management systems in the development of marine aquaculture, with the focus on four of the most important criteria associated with these systems: freshness, safety, traceability, and authenticity.
- Improved approach based on MALDI-TOF MS for establishment of the fish mucus protein pattern for geographic discrimination of Sparus aurataPublication . Freitas, Jorge; Silva, Pedro; Perestrelo, Rosa; Vaz-Pires, Paulo; Câmara, José S.Food fraud is still a recurrent practice throughout food supply chains. In the case of seafood, misidentification of species and products repackaging constitute the most common frauds. Therefore, the development of appropriate analytical approaches to be used against food fraud is necessary. The present study goal is to explore for the first time, the possibility to differentiate between Sparus aurata from two different mariculture farms located in Madeira Island (Caniçal and Ribeira Brava), using the mass fingerprint of fish mucus obtained from MALDI-TOF MS and analyzed using Mass-UP software for multivariate statistical analysis and biomarker identification. It was possible to establish, from the mucus protein fraction, a set of potential biomarkers for each location in a total of 35 peaks, being 17 peaks specific to Caniçal located farm and 18 to Ribeira Brava. The proposed analytical approach revealed a useful strategy providing accurate and fast results for fish geographical origin discrimination.
- Quality Index Method for fish quality control: Understanding the applications, the appointed limits and the upcoming trendsPublication . Freitas, Jorge; Vaz-Pires, Paulo; Câmara, José S.Background: The Quality Index Method (QIM) is a widely used approach for fish sensory grading, based on a structured scaling for freshness measurements, providing information concerning the fish freshness status, as a prediction of the remaining shelf-life for specific species or products. However, its tendency to be used in an oversimplified way and other common misapplications could lead to discredit of a methodology with great potential. Scope and approach: Review the principles of QIM methodology, discussing its concept, applications, and un derstand their limits, as a useful strategy to propose improvements, reinforce its predictive power and consequent acceptability. Key findings and conclusions: QIM methodology is based on a compromise between the number of fish samples necessary and the number of attributes, with sensory relevance in fish spoilage, that allows verifying if quality requirements are fulfilled. However, the assumptions inherent to the method, undermine the reliability of the shelf-life predictions. Determination of the variability associated with assessors, product, and correct structure of datasets for statistical analysis, will improve the predictive power of the method. However, it could lead to an increase in the method complexity that would drive it away from the industry’s needs for fast and easily implemented methods.
- A systematic AQbD approach for optimization of the most influential experimental parameters on analysis of fish spoilage-related volatile aminesPublication . Freitas, Jorge; Silva, Pedro; Vaz-Pires, Paulo; Câmara, José S.The volatile amines trimethylamine (TMA) and dimethylamine (DMA) could be used as important spoilage indices for seafood products, assisting in the determination of the rejection period. In the present study, a systematic analytical duality-by-design (AQbD) approach was used as a powerful strategy to optimize the most important experimental parameters of headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) conditions for the quantification of TMA and DMA in Sparus aurata. This optimization enabled the selection of the best points in the method operable design region for HS-SPME extraction (30 min; 35 ◦C; NaOH 15 M and NaCl 35%, w/v) and GC-MS analysis (80 ◦C; gradient 50 ◦C/min; flow rate 1 mL/min and splitless mode). The rejection day, estimated through the TMA concentration (>12 mg/100 g, at days 9–10), was compared with sensory (quality index method: day 7–8), physical (Torrymeter: day 8–9), and microbial (day 9–10) analysis, corroborating the suitability of the proposed approach for estimating the period for which they will retain an acceptable level of eating quality from a safety and sensory perspective.