Plasma-activated milk powder as a sodium nitrite alternative in pork sausages

This study investigated the effect of plasma activated milk powder containing 1.3 g/kg nitrite as an alternative to sodium nitrite in stored pork sausages. Control samples (NC) did not contain a nitrite source, while the recipes of other treatments contained 100 ppm sodium nitrite (PC), 5% plasma activated milk powder (PAMP), and 5% plasma activated milk powder with 0.05% ascorbic acid (PAMP+AA). The obtained results showed both experimental groups were characterized by higher values of residual nitrite, nitrosylhemochrome and redness as well as similar or lower values of thiobarbituric acid reactive substances and total aerobic plate count compared to PC group after the storage period. Using ascorbic acid promoted reduction of nitrite content and extended the color stability of the samples compared to PAMP group without deteriorating the oxidative and microbiological quality of the product. Finally, sausages cured using the proposed alternative method exhibited higher cooking yield, lighter color, better texture, and different aroma profile (PCA) than those with sodium nitrite.

Smartphone-based colorimetric study of adulterated tuna samples

In this work, a colorimetric analysis of adulterated tuna samples is carried out using both a spectroradiometer and a smartphone as capture devices. Yellowfin tuna (Thunnus albacares) slices were treated with nitrate and nitrite salts, as well as with two different vegetable extracts (beetroot and radish), and the resulting NO₂^- and NO₃^- concentration was analysed using HPLC-DAD. The results indicate that both nitrite and beetroot treatments work properly as colouring agents in tuna, being nitrate also effective. When assessing the effect of radish, the final flesh had a more whitish colour. Overall, this approach allows to obtain colorimetric data which can distinguish among the different adulterating agents.

Identification of nitrite treated tuna fish meat via the determination of nitrous oxide by head space-gas chromatography/mass spectrometry

Tuna fish meat is an expensive and highly perishable sea food. Fresh meat has a bright red colour which soon turns into an unsightly brown during storage. To prolong the aspect of freshness, the red colour is stabilised or even enhanced e.g. with carbon monoxide or nitric oxide, the product of a nitrite / ascorbic acid treatment, which bind as a ligand to myoglobin. These procedures are illegal. Here we present a method for identifying tuna meat samples, which have undergone fraudulent wet salting with nitrite. The method uses headspace-gas chromatography/mass spectrometry (GC/MS) for the determination of nitrous oxide, which is formed as the final product of the two-step reduction nitrite (added agent) to nitric oxide (ligand) to nitrous oxide (target compound). Complex bound nitric oxide is set free with sulfuric acid, which also promotes the reduction to nitrous oxide. The method was validated using ¹⁵N labelled nitrite as well as treated and untreated reference fish samples. A survey of 13 samples taken from the Swiss market in 2019 showed that 45 % of all samples were illegally treated with nitrite.

Increasing the Yield of Irish Brown Crab (Cancer pagurus) during Processing without Adversely Affecting Shelf-Life

During the processing of Irish Brown Crab (Cancer pagurus), protein and moisture are released and losses up to 10% (by weight) are common. The objective of this study was to investigate the use of clean label ingredients to reduce this loss, without adversely affecting shelf-life or promoting the growth of spoilage bacteria. Following preliminary studies, 5% (w/v) sodium caseinate (SC) and (5%, w/v) potato starch (PS), with and without (0.5%, w/v) ascorbic acid (AA) were selected. Ninety crabs (30 per treatment) were soaked and boiled in water (control 1), AA (control 2), SC, PS, SC plus AA, or PS plus AA and analyzed for cook loss as well as pH, aw, water holding capacity (WHC), and microbial shelf-life (total viable count (TVC), total Enterobacteriaceae count (TEC), and spoilage bacteria) during 28 days storage at 4 °C. On average, 11.1% of the control 1 weight was lost during processing. This was reduced to 8.0% when treated with AA (control 2) and to 3.5%, 4.7%, 5.8%, and 2.3% with SC, PS, SC plus AA, and PS plus AA, respectively. None of these treatments negatively impacted on shelf-life and similar growth curves were observed for TVC, TEC, Pseudomonas spp., Clostridium spp., lactic acid bacteria (LAB), and hydrogen disulphide producing bacteria, regardless of treatment. It was therefore concluded that, subject to sensory evaluation and validation under commercial conditions, these natural ingredients could be used to substantially increase the yield and hence commercial value of crab meat, without adversely affecting shelf-life.

Preservative Characteristics of Ascorbic Acid on Color, Texture and Fatty Acid of Cold-Smoked Fish

The objective of this study is to investigate the preservative characteristics of ascorbic acid (A) on the color, texture and fatty acids (FA) of cold-smoked fish. The fish (~250 g) were treated with six different formulation of brine prepared with 10% salt, which is the control(C), treated with 0.4% NaNO2 (N4), 0.2% NaNO2(N2) and only 2.5% A and their combinations (N4A, N2A). The sample groups were cold smoked, then stored at ±4°C and analyzed for 15 days intervals. The results showed that ascorbic acid did not have any negative effect on color, texture or sensory characteristics while there were significant preservative effects on FA. The most stable groups were N and A combinations. The PUFA (Polyunsaturated FA), PUFAω-3, PUFAω-6 and UFA (Unsaturated FA) of N4A and N2A were higher than group C and A. Accordingly, it is expected that, in terms of PUFAω-3 and PUFAω-6, the combination of N and A can contribute to the lipid stability.