Construction of IsoVoc Database for the Authentication of Natural Flavours.

Flavour is an important quality trait of food and beverages. As the demand for natural aromas increases and the cost of raw materials go up, so does the potential for economically motivated adulteration. In this study, gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) analysis of volatile fruit compounds, sampled using headspace-solid phase microextraction (HS-SPME), is used as a tool to differentiate between synthetic and naturally produced volatile aroma compounds (VOCs). The result is an extensive stable isotope database (IsoVoc-Isotope Volatile organic compounds) consisting of 39 authentic flavour compounds with well-defined origin: apple (148), strawberry (33), raspberry (12), pear (9), blueberry (7), and sour cherry (4) samples. Synthetically derived VOCs (48) were also characterised. Comparing isotope ratios of volatile compounds between distillates and fresh apples and strawberries proved the suitability of using fresh samples to create a database covering the natural variability in δ13C values and range of VOCs. In total, 25 aroma compounds were identified and used to test 33 flavoured commercial products to evaluate the usefulness of the IsoVoc database for fruit flavour authenticity studies. The results revealed the possible falsification for several fruit aroma compounds.

Assessment of trans-fatty acid content in a sample of foods from the Slovenian food supply using a sales-weighting approach.

OBJECTIVE: Consumption of trans-fatty acids (TFA) is a well-established risk factor for CVD morbidity and mortality. Our objective was to investigate TFA levels in Slovenian food supply. DESIGN: Cross-sectional study. SETTING: Selected foods (n 282) were purchased in Slovenia (2016), and the TFA content was determined. The sample included pre-packed foods with/without declared partially hydrogenated vegetable oils (PHO), as well as non-pre-packed foods. A sales-weighting approach was used to ponder different market shares of the products. RESULTS: While the majority of the investigated samples had low levels of TFA, up to 6·8 g of TFA per 100 g of food was observed in certain foods. Within pre-packed foods (n 207), the highest proportion of samples with high TFA levels was found among cookies with labelled PHO: 69 % (n 18) would exceed European Union regulatory TFA limit (2 g industrial TFA per 100 g of fats), which will be implemented in April 2021. Among the investigated non-pre-packed foods (n 75), only croissants contained notable TFA levels (mean 0·90 (sd 0·97); maximum 3·3 g/100 g), with about half of the samples exceeding 2 g TFA per 100 g of fats. CONCLUSIONS: In 2016, some foods in Slovenian food supply still contained notable amounts of TFA. Foods with listed PHO as an ingredient were usually higher in TFA as compared with foods not labelled to contain PHO. Biscuits were identified as the most concerning category of pre-packed foods, while croissants contained highest levels of TFA within non-pre-packed foods.

Lactic Acid Fermentation of Arthrospira platensis (Spirulina) in a Vegetal Soybean Drink for Developing New Functional Lactose-Free Beverages.

The main objective of this study was to evaluate the suitability of Arthrospira platensis F&M-C256 (spirulina) biomass in a vegetal soybean drink or in water, as substrate for lactic acid fermentation by the probiotic bacterium Lactiplantibacillus plantarum ATCC 8014 (LAB8014) and to evaluate the fermented products in terms of bacteria content and organic acids content, biochemical composition, total phenolics, and phycocyanin content, in vitro digestibility, in vitro and in vivo antioxidant activity. After 72 h of fermentation, a bacterial concentration of about 10.5 log CFU mL-1 in the broths containing the soybean drink + spirulina + LAB8014 (SD + S + LAB8014) or water + spirulina + LAB8014 (W + S + LAB8014) was found. Lactic acid concentration reached similar values (about 1.7 g L-1) in the two broths, while a different acetic acid concentration between SD + S + LAB8014 and W + S + LAB8014 broths was observed (7.7 and 4.1 g L-1, respectively). A. platensis biomass was shown to be a suitable substrate for LAB8014 growth. After fermentation, both broths contained a high protein content (>50%). In both broths, total phenolics, in vitro and in vivo antioxidant activity increased after fermentation (+35, +20, and +93% on average, respectively), while phycocyanin content decreased (-40% on average). Digestibility of W + S + LAB8014 broth statistically improved after fermentation. This study highlights the potential of A. platensis F&M-C256 biomass as a substrate for the production of new functional lactose-free beverages.

Non-Thermal Ultrasonic Extraction of Polyphenolic Compounds from Red Wine Lees.

This study presents the results of conventional aqueous (CE) and non-conventional ultrasound-assisted (UAE) extractions of polyphenolic compounds from lees extracts of red wine varieties (Merlot and Vranac). The effect of ultrasound extraction time (t, s), and amplitude (A,%) from a 400 W ultrasound processor with different ultrasonic probes diameters (Ds, mm) on the amount and profile of polyphenolic compounds in the obtained extracts was investigated and compared to CE. The optimal conditions resulting in maximum extraction of phenolic compounds were: Probe diameter of 22 mm, amplitude 90% and extraction time for Vranac wine lees 1500 s and for Merlot wine lees extraction time of 1361 s. UAE proved to be significantly more effective in enhancing the extraction capacity of trans-resveratrol glucoside (30.57% to 300%), trans-resveratrol (36.36% to 45.75%), quercetin (39.94% to 43.83%), kaempferol (65.13% to 72.73%), petunidin-3-glucoside (41.53% to 64.95%), malvidin-3-glucoside (47.63% to 89.17%), malvidin-3-(6-O-acetyl) glucoside (23.84% to 49.74%), and malvidin-3-(6-O-p-coumaroyl) glucoside (26.77% to 34.93%) as compared to CE. Ultrasound reduced the extraction time (2.5-fold) and showed an increase of antioxidant potential by 76.39% (DPPH) and 125.83% (FRAP) compared to CE.

Authentication of key aroma compounds in apple using stable isotope approach.

Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) for the analysis of key volatile compounds sampled using headspace solid phase microextraction (HS-SPME) is an appropriate tool for authenticity assessment of apple aromas. The current research characterises 18 laboratory produced and 15 commercial apple recovery aroma samples, establishes a database of δ13C values of 16 aroma compounds with respect to their origin (synthetic and natural), and assesses the authenticity of commercially available aroma compounds. Analysis of so-called natural aroma products, revealed δ13C values that were within the expected authentic range although the data did reveal possible falsifications. The sensitivity of the method was evaluated through simple isotope mass balance calculation. Falsification identification is possible for most aromatic substances when the amount of added synthetic compound is in tens of percent.

Disaccharides: Influence on Volatiles and Phenolics of Sour Cherry Juice.

The food industry is continuously developing ingredients, processing methods and packaging materials to improve the quality of fruit products. The aim of this work was to study the effect of sugars, a common ingredient in the food industry, on phenolics and volatiles of sour cherry juice. Sucrose, trehalose and maltose chemical isomers were chosen for this investigation. All sugars influenced the evaluated parameters. Samples with maltose addition had lower, while samples with sucrose and trehalose addition had higher anthocyanin content than the control sample. Generally, trehalose had a higher positive effect on volatiles with the desired flavor note.

Generation of Lactobacillus plantarum strains with improved potential to target gastrointestinal disorders related to sugar malabsorption.

Malabsorption of dietary sugars is a common cause of gastrointestinal discomfort, affecting up to one in three people with debilitating symptoms, such as abdominal pain, osmotic diarrhoea, bloating and flatulence. Besides dietary interventions, it has been suggested that ingestion of lactobacilli may alleviate these symptoms. The objectives of this study were to generate strains with improved potential to ameliorate sugar malabsorption related gastrointestinal disorders. Initial selection was made from 183 natural isolates of lactic acid bacteria, on the basis of broad sugar fermentation ability, absence of gas production, gastrointestinal survival and susceptibility to important medical antimicrobials. Two strains of L. plantarum (KR6 and M5) exhibited favourable characteristics for all criteria, and were further optimised through random mutagenesis and selection approaches. Ultraviolet light (UV) exposure resulted in mutants characterized by better survival (for 1.9 log and 1.4 log) in gastrointestinal conditions. Subsequent exposure to ethyl methanesulfonate (EMS) provided mutants with greater tolerance to glucose induced catabolic repression. UV and UV-EMS mutants of L. plantarum M5 showed improved adhesion ability. As a result of this optimisation, L. plantarum MP2026 and L. plantarum MP2420 have been identified as promising candidates for probiotics, intended for alleviation of gastrointestinal discomfort originating from sugar malabsorption.

Influence of Yellow Light-Emitting Diodes at 590 nm on Storage of Apple, Tomato and Bell Pepper Fruit.

The objective of this study is to investigate the effects of irradiation from light-emitting diodes (LEDs) on several fruits during storage. To improve storage and increase the contents of some bioactive compounds, apple, tomato and red bell pepper fruits were exposed to yellow light emitted from the diodes at 590 nm. The contents of ascorbic acid, total phenolics, total flavonoids and several pigments were investigated, along with the antioxidant potential. The colour parameters (L*, a* and b*) and firmness of the fruit were also determined. After 7 days of LED light irradiation, there was significantly higher total phenolic content and antioxidant potential in apple peel extracts. The irradiated fruit of tomato had significantly higher levels of total phenolic compounds, and the fruit of red bell pepper had significantly higher antioxidant potential. LED light had no effects on the colour parameters, although there was a tendency to accelerate colour development. Apple fruit irradiated with LED light was significantly less firm. Among twelve analysed pigments, significantly more ß-carotene was detected in LED light-irradiated apple and bell pepper fruit, more α-tocopherol and γ-tocopherol in bell pepper fruit, and more lutein in apple peel and bell pepper fruit. The applied LED light slightly accelerated the ripening of the studied fruit, and affected the synthesis of some of the secondary metabolites.

Effect of trehalose addition on volatiles responsible for strawberry aroma.

Aroma is one of the most important quality properties of food products and has a great influence on quality and acceptability of foods. Since it is very difficult to control, in this study the effect of addition of trehalose (3, 5 and 10%) to freeze-dried strawberry cream fillings was investigated as a possible means for retention of some of the aroma compounds responsible for the strawberry aroma. In samples with added trehalose, higher amounts of fruity esters were determined. Increase of trehalose content did not cause a proportional increase in the amount of fruity esters. However, results of our research showed that trehalose addition did not have the same effect on both gamma-decalactone and furaneol.