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Canned pickled cucumbers, tomato paste, and olives are three commonly consumed products in Iranian households that may be a source of heavy metals for individuals due to the type of packaging. Therefore, in this study, samples of these three types of food were collected from the market and were measured for mineral and heavy metal content. The levels of metals including Cadmium, Copper, Arsenic, Iron, Lead, and Zinc were determined using an AAS- Flame and Graphite furnace. Moreover, the concentrations of Mercury and Tin were determined using the ICP-MS. In canned cucumber samples, only two metals, tin and lead, were detected. The levels of heavy metals in these three products were compared using statistical tests. A significant difference was observed in the amount of cadmium ( p  < 0.05). The average lead content in these three products was above the permissible limit. The levels of copper, arsenic, iron, cadmium, zinc, mercury, and tin in the canned food samples were found to be within the acceptable limits set by national and international regulatory authorities.

Pickled cucumber is a favorite pickle product of the general public, but the long-term or excessive consumption of traditional high-salt pickles seriously threatens people’s health. In this paper, after the subject samples were pickled according to the process flow, one-way and orthogonal tests were designed to experiment with the optimum additive amount of composite pickling agent for cucumber, and meanwhile, the amino acid content of cucumber in different pickling methods was calculated. The Gaussian process regression model’s learning process was optimized by choosing the squared exponential covariance function. The cuckoo search algorithm is proposed, and the improvement of the cuckoo search algorithm is achieved by combining step length adaptive change calculation and chaotic sequences. Jointly improve the cuckoo search algorithm and Gaussian process algorithm, construct the agent model of the pickled cucumber recipe, get the final pickled cucumber recipe parameter design results, and verify the optimization effect of the process through the control experiment. The experimental results show that the best pickling combination is the composite pickling agent with 0.1% addition of acetic acid, 1.5% addition of mannitol and 0.06% addition of calcium lactate, and the sensory score of the cucumber pickled from that place is 92.8564. After optimization, the amino acid content of the cucumber pickled using the composite pickling agent is only 0.03889g/100g, and the quality of the cucumber has been improved.

The permeation kinetics of nano-emulsified tarragon essential oil (TEO) into fermented pickled cucumber texture was measured by Fourier transform infrared spectrometry (FT-IR) and antioxidant capacity potentiometry. The objective was to evaluate how nano-emulsion affect the sensory, antioxidant, physicochemical, and microbial flora characteristics of the pickled cucumbers. Oil-in-water nano-emulsions (100, 200, 400 and 800 mg L −1 ) were prepared by ultrasonic waves and were added to the brine/vinegar and cucumber mixture. The analysis of chemical compounds by gas chromatography showed that the main components of TEO were methyl chavicol, Z-β-ocimene, E-β-ocimene, limonene, and methyl eugenol. The average particle size of nano-emulsions was ranging from 19.03 to 218.6 nm. The sensory evaluation of pickled cucumber containing nano-emulsified TEO showed that higher TEO concentrations increased the sensory characteristics significantly in the pickled cucumbers, such as their color, aroma, taste, mouthfeel, texture crispness, and overall acceptance. The microbial test proved the inhibitory effect of TEO on Penicillium expansum and Aspergillus flavus species. According to the results of FTIR, the nano-emulsified TEO penetrated well into the pickled cucumber texture. The antioxidant capacity of the pickled cucumbers revealed that by increasing the concentration of TEO, the antioxidant capacity of the pickled cucumber texture increased significantly ( p  < 0.05). Using nano-emulsified TEO can be a good replacement for dried vegetables in producing fermented pickled cucumbers. Graphical Abstract

Lactic acid bacteria (LAB) have the potentials to produce antimicrobial peptides against pathogens, and grow on traditional fermented foods such as pickled cucumber, which is widely consumed in Indonesia. LAB convert carbohydrates into organic acids, while hydrogen peroxide and antimicrobial peptides inhibit the growth of spoilage bacteria. The present work aimed to identify the antibacterial activity of LAB strains isolated from pickled cucumber. The strains were morphologically and physiologically identified, and selected based on their ability to inhibit the indicator bacteria using the well-diffusion agar method. Furthermore, the identification based on biochemical and molecular tests were carried out on strains with antibacterial activity. The present work isolated four LAB strains, namely S1K2T1, S5K7T1, S5K8T1, and S10.2K6, with antibacterial activities which varied from medium to strong. Strains S1K2T1, S5K7T1, S5K8T1, and S10.2K6 had inhibitory activity against pathogenic bacteria. Strain S1K2T1 had strong inhibition against Sta. aureus ATCC 2592.3. Strain S5K7T1 had strong inhibition against Sal. Typhi BPE 122.4 CCA. Strain S10.2K6 had strong inhibition against P. putida FNCC 0071. Strain S5K8T1 had medium inhibition against both B. subtilis ATCC 6633 and P. putida FNCC 0071. The four LAB strains were identified as Lactobacillus plantarum based on API 50CHL test and phylogenetic analysis of 16S rRNA genes. The plnA gene was detected in the four strains, and identified as a bacteriocin protein from L. plantarum.

Salt content and soluble solid content are important test indicators of quality in pickled products according to commercial standards. Pickled cucumber contains many organic compounds and free ions, and its juice, acting as the secondary coil under alternating magnetic flux, shows specific electrical characteristics during pickling. This study applied a detection system based on the o-core transformer to determine the NaCl content (N c) and soluble solid content (SSC) of pickled cucumber in the extreme low-frequency range of 50 to 400 Hz at room temperature. It is interesting to note that the changes in electrical properties during pickling resulted in impedance changes in the coils of cucumber juice. Results showed that the terminal voltage (U ₛ) in the secondary circuit was positively correlated with NaCl content and SSC, due to the increase of conductivity in the coil. The inductive current was the ratio of the inductive voltage to the total impedance in the secondary circuit, which increased according to Ohm’s law, resulting in an increase of terminal voltages (U ₛ) related to the physicochemical properties of the samples, particularly the amount of free ions. The λ value was found to be more effective than U ₛ in evaluating the NaCl content (N c), while the most effective regression model for predicting SSC was obtained at a primary voltage of 30 V and a frequency of 120 Hz based on U ₛ value. The proposed method laid the foundation to investigate the response characteristics of food materials by combing magnetic flux with transformer properties.

Fermented cucumber pickles are the lactic acid fermentation products formed through the influence of microorganisms present in the environment. This study investigated the impacts of starter cultures, namely, Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus paraplantarum, typically utilized for the fermentation of traditional pickled gherkins, on fermentation process. The chemical (pH, total acidity and salt) and microbiological (total mesophilic aerobic bacteria, lactic acid bacteria and yeast-mould) changes were observed against the control sample during fermentation process. Moreover, the amounts of biogenic amines (BAs) and metabolites formed as a consequence of fermentation were determined using HPLC. It was found that the chemical analyses provided similar results for all the samples. The amount of total mesophilic aerobic bacteria and yeast-mould colonies in pickle sample containing L. plantarum 49 strain appeared to reduce significantly. The amount of BAs was the lowest for the pickle samples where L. plantarum strains were added. The amount of BAs was below the toxic value that could affect human health. More BAs were synthesized as the fermentation period increased. Lactate was seen to exist in the samples when pyruvate was present, and acetoin was converted into 2.3-butanediol during the fermentation period. It was concluded that the pickle sample for which L. plantarum 49 strain was used displayed a better fermentation profile (i.e., metabolite and biogenic amines) than the remaining samples. Producing a more delicious and reliable product using such characteristics of L. plantarum strains in pickled gherkins is believed to significantly contribute to the food industry.

High-salt samples present a challenge to mass spectrometry (MS) analysis, particularly when electrospray ionization (ESI) is used, requiring extensive sample preparation steps such as desalting, extraction, and purification. In this study, infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) coupled to a Q Exactive Plus mass spectrometer was used to directly analyze 50-μm thick slices of cucumber fermented and stored in 1 M sodium chloride brine. From the several hundred unique substances observed, three triterpenoid lipids produced by cucumbers, β-sitosterol, stigmasterol, and lupeol, were putatively identified based on exact mass and selected for structural analysis. The spatial distribution of the lipids were imaged, and the putative assignments were confirmed by tandem mass spectrometry performed directly on the same cucumber, demonstrating the capacity of the technique to deliver confident identifications from highly complex samples in molar concentrations of salt without the need for sample preparation. Graphical Abstract ᅟ

Quality of Fresh and Processed Red Beet from Organic and Conventional Cultivation The aim of this study was to evaluate the biological value of fresh red beet and sensory quality of pickled red beet prepared from roots from organic and conventional cultivation systems. Two cultivars of red beet cv. Czerwona Kula and cv. Opolski were grown by conventional and organic systems in the years 2008-2009 on certificated Experimental Field of Research Institute of Vegetable Crops in Skierniewice. Chemical analyses of fresh red beets were carried out immediately after harvest but the sensory evaluation of pickled beets was carried out by trained panel according to PN-ISO guidelines applying the sensory profiling analysis. Results have shown that the method of cultivation had a positive effect on the chemical composition of fresh roots of red beet. The roots of both cultivars from organic cultivation contained significantly more dry matter, sugars and betanins, and accumulated less nitrate than roots from conventional cultivation. There was no significant effect of cultivar and method of cultivation on the overall sensory quality of pickled red beets. Comparison of sensory evaluation for pickles of two cultivars from organic cultivation showed that canned red beets from cultivar Czerwona Kula characterized by slightly darker color, firmer flesh and more typical taste of red beet as compared to samples from cultivar Opolski. Pickled red beets from conventional cultivation characterized by firmer flesh compared to the pickled beets from organic cultivation, more noticeable taste of pickled cucumbers and flavor of fruit.