D-Fructose/D-Glucose Assay Kit

Many of the enzymatic test kits are official methods of prestigious organisations such as the Association of Official Analytical Chemicals (AOAC) and the American Association of Cereal Chemists (AACC) in response to the interest from oenologists. Megazyme decided to use its long history of enzymatic bio-analysis to make a significant contribution to the wine industry, by the development of a range of advanced enzymatic test kits. This task has now been successfully completed through the strategic and comprehensive process of identifying limitations of existing enzymatic bio-analysis test kits where they occurred, and then using advanced techniques, such as molecular biology (photo 1), to rapidly overcome them. Novel test kits have also been developed for analytes of emerging interest to the oenologist, such as yeast available nitrogen (YAN; see pages 2-3 of issue 117 article), or where previously enzymes were simply either not available, or were too expensive to employ, such as for D-mannitol analysis.

It is without doubt that testing plays a pivotal role throughout the whole of the vinification process. To produce the best possible quality wine and to minimise process problems such as “stuck” fermentation or troublesome infections, it is now recognised that if possible testing should begin prior to harvesting of the grapes and continue through to bottling. Traditional methods of wine analysis are often expensive, time consuming, require either elaborate equipment or specialist expertise and frequently lack accuracy. However, enzymatic bio-analysis enables the accurate measurement of the vast majority of analytes of interest to the wine maker, using just one piece of apparatus, the spectrophotometer (see previous issue No. 116 for a detailed technical review). Grape juice and wine are amenable to enzymatic testing as being liquids they are homogenous, easy to manipulate, and can generally be analysed without any sample preparation.

Purpose: Inulin-type fructans (ITF) are fermentable dietary fibres (DF) that can confer beneficial metabolic health effects through changes in the gut microbiota. Many papers suggest that complex food rich in DF could be more relevant than purified DF in terms of health effect. We compared the prebiotic effect of natural source of inulin (scorzonera) versus native inulin extracted from chicory root in a model of obesity.Methods: Mice were fed during 6 weeks a low-fat (LF), high-fat (HF) or high-fat diet enriched with either purified inulin from chicory root (Inu) or lyophilized scorzonera (Sco), with the same amount of ITF intake (10%) versus a non-fermentable fibre (cellulose). Metabolic parameters were correlated with the gut microbiome composition (16S rRNA gene sequencing).Results: Both inulin sources reduced food intake without significantly modifying body weight gain or adiposity compared to HF. Purified inulin and lyophilized scorzonera differentially modulate the gut physiology and microbiota. Both inulin and scorzonera shifted global gut microbial composition from HF group, decreased members of Desulfovibrionaceae and boosted bifidobacteria level. Some effects were specific to Sco group, such as the increase of Akkermansia and the decrease of Bacteroides, that correlated to biological outcomes. Inu improved hepatic steatosis whereas scorzonera boosted intestinal immunity markers and antimicrobial peptides expression, and increased intestinal crypt depth. Conclusion: Differences occur between natural edible versus isolated sources of ITF. Both sources of inulin shifted the gut microbiota, but differently affected intestinal and lipid homeostasis. This study highlights the importance of food matrix and origins of fructans for their use in the context of metabolic disorders.

This study investigates the combined effects of l-asparaginase pretreatment enzyme (10,000 ASNU/L) with three different frying techniques: deep, microwave, and air frying on acrylamide (AA) formation in French fries. Acrylamide content was analyzed using ultra-high performance liquid chromatography coupled with a Diode Array Detector The study reveals that air-fried potatoes contained the highest AA content among the three frying methods without enzyme pretreatment (963.83 µg/kg). In contrast, microwave-fried potatoes had the lowest (785.31 µg/kg). The enzymatic pretreatment significantly reduced AA levels particularly in microwave-fried potatoes, which recorded 482.28 µg/kg and 475.60 µg/kg after 20 and 30 min of enzyme treatment, respectively. These levels are below the reference threshold of 500 µg/kg as defined by Regulation (EU) 2158/2017. This study demonstrates that combining l-asparaginase treatment with microwave frying can effectively mitigate AA levels in French fries by providing a healthier alternative to conventional frying methods.

Pasta made from durum wheat semolina has a medium–high glycemic index score, high starch digestibility, and limited nutritional value due to its low fiber, vitamin, and bioactive compound content. This study aimed to enhance pasta’s nutritional and functional qualities by incorporating Pleurotus eryngii (PE) powder at various substitution levels to achieve one nutritional claim at least. This research involved two phases: evaluating the chemical/physical, nutritional, functional, and sensory properties of laboratory-scale samples and validating the selected formulations through industrial-scale production and shelf-life analyses. The pasta sample with 8.62% PE substitution (SPE8-P) demonstrated significantly improved nutritional qualities, including high fiber content sufficient for a “high fiber content” claim, and potential prebiotic activity indicated by increased bifidobacterial density during simulated fecal microbiota fermentation. Despite its enhanced riboflavin and antioxidant content, regulatory constraints limited the inclusion of claims for vitamin B2 richness and antioxidant activity. Although significantly affecting the color, taste, and odor profiles, the sensory analysis revealed high overall acceptability, supporting the product’s potential for consumer acceptance. This study confirms the feasibility of producing innovative, nutritionally enriched pasta with PE powder as a functional ingredient. Future research will focus on in vivo evaluation to establish the potential for classifying this pasta prototype as a functional food.

One of the most relevant challenges in winemaking is the increase in the alcohol content of wine, mainly due to climate change. The use of selected non-Saccharomyces yeasts in sequential fermentation with Saccharomyces cerevisiae is one of the effective strategies for dealing with this issue, even if it has been poorly confirmed at the winery level. This work evaluated the use of Starmerella bombicola and commercial S. cerevisiae strains in sequential fermentation at pilot scale in winery conditions to reduce the ethanol content and obtain a wine with enhanced aroma complexity. The results showed that the sequential S. bombicola/S. cerevisiae fermentation in aeration conditions (20 mL/L/min for the first three days) resulted in a reduction in ethanol of 0.80% (v/v) compared to pure S. cerevisiae fermentation. The aeration conditions of sequential fermentation did not affect the fermentation performance of yeasts. The winery conditions determined, in the sequential fermentation modalities, an enhancement of wild yeasts’ presence. At the same time, the inoculation of S. bombicola determined an enhancement of glycerol and lactic acid, which positively influences the structure and body of the wine as well as specific aromatic notes. In winery conditions, better control of fermentation is needed to achieve potential ethanol reduction and favorable by-product formation using S. bombicola.

Lettuce (Lactuca spp.) is one of few edible plant species that produce latex. During lettuce harvest, latex leaks from ruptured laticifers onto the cut stem and adheres to other lettuce heads, harvesting tools, and packaging. Little is known about the colonization of lettuce latex by Shiga toxin-producing E. coli O157:H7 (EcO157), the main causal agent of outbreaks linked to lettuce. We screened 14 lettuce genotypes, including wild lettuce and commercial morphological types, for EcO157 multiplication in their latex-coated cut stems. Change in EcO157 density after its inoculation into the latex of these genotypes differed significantly and ranged from a 1.7× decline to a 3.6× increase over 6 h at 25°C. EcO157 density increased in all genotypes except one, a romaine lettuce breeding line that caused decline of the pathogen. Latex biochemical properties, such as concentration of sucrose, glucose, fructose, phenolic compounds and H₂O₂, and peroxidase (POD) activity, were quantified in all genotypes. These traits varied significantly among genotypes, but only POD activity correlated significantly with the change of EcO157 density in the latex (r = −0.553). Total phenolics and H₂O₂ concentrations were also negatively and significantly correlated with each other (r = −0.608). The inhibitory effect of POD on EcO157 multiplication in lettuce latex and the identification of a genotype that causes decline of the pathogen in its latex may serve as new phenotypic and genotypic tools to control microbial contamination of lettuce at harvest. Their integration in lettuce breeding programs may enhance the microbial safety of lettuce.

The Maillard reaction (MR) between sugars and amino acids, peptides, or proteins is understood to occur gradually during the production and aging of sparkling wines, where it contributes to caramel, roasted, and toasted aromas. Divalent metal ions can accelerate the MR, although this has not been previously reported in wine or wine-like conditions. In this work, the effect of calcium (Ca) and magnesium (Mg) ions on the concentration of 10 Maillard reaction-associated products (MRPs) was measured in modified sparkling base wine during accelerated aging at 50 °C for four weeks. Chardonnay base wine was modified by the addition of fructose (0.02 M) and a single amino acid (lysine, glycine, cysteine; 0.01 M) in combination with Ca²⁺ or Mg²⁺ at zero, low (10 mg/L), or high (50 mg/L) dose levels. MRPs were quantified by headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC/MS), sugar concentration was measured by enzymatic assay, and amino acids and free metal ions were monitored by capillary electrophoresis. Fructose levels did not substantially decrease during aging despite increases in all MRPs, suggesting that trace sugars or α-dicarbonyl species present in the wine matrix likely play a greater role in MRP formation than fructose. Aging duration and amino acid content had a greater effect than metal addition on the composition of the MRPs. Treatments containing cysteine and 50 mg/L Ca²⁺ had elevated concentrations of benzaldehyde and furfural ethyl ether following 4 weeks of accelerated aging. This work identified key MRPs that increase during base wine accelerated aging and informs future research on the relationship between wine composition and aging markers.

The aim of this study was to examine how silages from different grassland species and harvesting frequencies affect feed intake, milk production, and methane (CH₄) emission in dairy cows. We hypothesized that cows consuming silages of more frequent harvest, grass species with greater organic matter digestibility and legumes with lower NDFom concentration would have greater silage dry matter intake and milk yield and thereby lower CH₄ yield and intensity. Forty Norwegian Red cows were allocated to 5 treatments in a cyclic changeover design with 4 21-d periods (14 d of adaptation, 7 d of data collection). The 5 treatments evaluated were silages produced from timothy (Phleum pratense L.) in a 3-cut system (T3), timothy in a 2-cut system (T2), perennial ryegrass (Lolium perenne L.) in a 3-cut system (PR3), red clover (Trifolium pratense L.) in a 3-cut system (RC3) and a mix of T3 and RC3 (50:50 on DM basis) (T3/RC3). The treatments were prepared by mixing silages from each crop over the growing season, proportional to the harvested DM yield of each cut. Cows were offered the mixed silages ad libitum supplemented with a fixed level of concentrate. Gas emissions were measured using 2 Greenfeed units. Milk yield was recorded in the milking robot at each visit, and milk samples were collected at 3 consecutive milkings during the last 7 d of each period. Cows were weighed after each milking, and total-tract digestibility of each diet was estimated using acid insoluble ash as internal marker in fecal grab samples. The data were analyzed using the MIXED procedure of SAS with block, period and treatment as fixed effects and animal within block as random effect. Silage and total DMI did not differ between T3 and T2, but total DMI was lower for PR3 than for T3. There was a quadratic effect of increased proportion of red clover, with highest intakes of T3/RC3 and lower intakes of RC3 than of T3. Energy corrected milk (ECM) yield was lower for T2 than T3, and for PR3 than T3. There was a quadratic effect of increased proportion of red clover, with highest ECM yield in T3/RC3 and lower in RC3 than in T3. Organic matter digestibility was lower for T2 than T3, but it did not differ between T3 and PR3. Including red clover in the diet linearly decreased organic matter digestibility. Methane production (g/d) did not differ between T3 and T2, but CH₄ intensity (g/kg ECM) was greater for T2 than for T3. There was no difference between T3 and PR3 for CH₄ production but yield and intensity were greater for PR3 than T3. Including red clover in the diet linearly increased CH₄ production, yield and intensity with greatest intensity in the 100% red clover diet. In conclusion, changing harvesting frequency for timothy from 2 to 3 harvests per year did not affect CH₄ production or yield, but CH₄ intensity was reduced. Replacing timothy with perennial ryegrass and increased inclusion rate of red clover both increased CH₄ yield and intensity.

Andean blackberries are appreciated for their unique flavor, high nutritional quality, and antioxidant properties. In this study, the effectiveness of low doses (0.4; 0.5; 0.6 and 0.7 µL l^-1 for 3 min) of gaseous ozone as an elicitor for health-promoting compounds was evaluated during 10 d of storage at 6 ± 1°C. The physicochemical and sensory quality of the fruit was also determined. Ozone was used in a single application before storage. Initially, regardless of the dose applied, no negative effects of the O₃ treatments were observed in any of the parameters studied. In addition, the firmness, the antioxidant activity and the fructose, vitamin C and polyphenols contents were higher in the O₃-treated fruit compared to the control. During storage, these differences were maintained except for the 0.7 µL L^-1 dose. This indicates that low concentrations of gaseous O₃ could promote the synthesis of biocompounds and be effective in maintaining the postharvest quality of blackberries for at least 4 days of refrigerated storage. However, more research is needed to maintain these advantages during longer storage periods.

Background: The role of the S. cerevisiae strain in defining the volatile fingerprint is expressed throughout alcoholic fermentation and post-fermentation sur lie aging and is crucial for customizing the wine style. Methods: In this study, the alcoholic fermentation was carried out in a synthetic must to exclusively bring out the performance of the yeast in terms of volatile compound production, excluding the effect of the grape. Results: Among the 33 volatile organic compounds identified in the synthetic wines by GC-MS, esters, alcohols, and acids, represented the major groups for the nine different commercial oenological strains tested. All the relevant differences in the volatile fingerprint of the synthetic wines, which were lab-scale fermented, were quantitative rather than qualitative. The clustergram representation of the volatiles revealed an outstanding fingerprint for two strains (VIN13 and VIN7) among those tested, featuring hexanoic acid, octanoic acid, the corresponding esters (ethyl hexanoate, ethyl octanoate), and the acetates (2-phenylethyl acetate, isoamyl acetate), all at the highest levels. No relationship was appreciated between the fermentation rate and the volatile fingerprints. Conclusions: The outcomes of this study address the wine industry’s needs, supplying a full characterization of a broad range of commercial yeasts’ ability in fermentative volatile production.

Noble rot, caused by infection of grapes with the fungus Botrytis cinerea, is commonly used in the production of dessert-style white wines, imparting desirable aroma descriptors, including dried fruit, honey, and stone fruit. γ-Nonalactone is an aroma compound that is ubiquitous in wine yet has been overlooked in literature for some time. Previously, this compound has been found in higher concentrations in noble rot wines. New Zealand (NZ) is world-renowned for its high-quality white wines, particularly Sauvignon blanc; however, limited research has been carried out on the aroma features of wines produced in lower volumes, such as botrytised dessert styles, and those produced from aromatic grape varieties such as Riesling. Therefore, this work quantified γ-Nonalactone concentrations in 38 NZ commercial white wines, representing botrytised (18) and non-botrytised (20) styles, using SIDA-SPE-GC-MS. These wines were selected to represent a cross-section of NZ white wines, made from Sauvignon blanc, Riesling, and Sauvignon-Sémillon blends, and derived across a range of vintages (2014–2021), and NZ wine regions (Central Otago, Gisborne, Hawke’s Bay, Marlborough, Waiheke Island, Waipara Valley, and Wairarapa). Multivariate data analyses were carried out using vitivinicultural data from wine producers, wine, and measured technical parameters and γ-Nonalactone concentrations. Analyses revealed that γ-Nonalactone concentration was significantly higher in botrytised wines (p-value = 3 × 10^-8), with a maximum of 43.5 µg L^-1, compared to a maximum of 8.7 µg L^-1 in the non-botrytised samples. No significant associations were found between γ-Nonalactone concentration and region or grape variety, suggesting that the precursors to γ-Nonalactone are produced by B. cinerea itself, or through alterations in grape metabolism induced by B. cinerea. Additional research is needed to elucidate the mechanism(s) by which noble rot leads to higher γ-Nonalactone concentrations in wines.

Acrylamide is the main contaminant for starchy foods cooked at temperatures above 120 °C. It represents a potential carcinogen, and consequently, its reduction is important for safeguarding global health. The L-asparaginase enzyme catalyses the hydrolytic cleavage of L-asparagine, a precursor of acrylamide, into L-aspartic acid and ammonia, thus reducing the formation of acrylamide. The objective of this work was to test the enzyme L-asparaginase at two concentrations (150 and 300 U/kg flour) under normal baking conditions to reduce acrylamide. The results showed that the use of 300 U/g of the enzyme led to a reduction of 78% in acrylamide, meeting the reference level reported by Reg. (EU) 2017/2158 (50 μg/kg) without influencing parameters such as colour that impact the final characteristics of the product.

Potato chips are a popular snack, well-liked because of their texture-flavor combination. Potato chips are made by frying slices of potato in vegetable oil to achieve a crispy texture. Frying potato slices initiates the Maillard reaction, resulting in chemical changes that enhance taste, color, and texture, but also undesired acrylamides, which are suspected carcinogens. The application of pulsed electric field (PEF) technology is commonly used in French fry processing operations to prolong cutting blade sharpness and reduce waste, energy consumption, and water usage. Despite these attributes, PEF systems have not yet gained widespread adoption by potato chip producers. In the current study, Lamoka potatoes were PEF-treated prior to continuous frying into potato chips. The effect of specific energy at 0.75 kJ/kg (Low-PEF) and 1.5 kJ/kg (High-PEF) and electric field strength of 1 kV/cm, frequency of 24 kV, and pulse width of 6 μs versus untreated (control) samples was studied, then batches of 250 g of slices were fried at 170°C or 185°C for two frying times to obtain potato chips with acrylamide levels below the California Proposition 65 limit (275 ng/g). The Lamoka potato chip product quality metrics that were assessed include moisture, fat, reducing sugars, asparagine, acrylamide, chip color, and texture. PEF treatment of Lamoka potatoes resulted in chips fried in 10% less time, lower oil content by 8%, and a decrease of reducing sugars by 19.2 %, asparagine by 42.0%, and acrylamide by 28.9%. The PEF fried chips were lighter in color but maintained textural attributes compared to continuous frying cooking. The process of frying potato slices at 170°C for 150s with High-PEF yielded potato chips with acrylamide content below the California Proposition 65 limit; which speaks to the health implications for consumers and the quality and safety of these chips.

Manna, a well-known herbal drug has multiple traditional and pharmaceutical uses and the entire composition, sugar derivatives and polyphenols, gives rise to a very interesting bioactive complex with versatile therapeutic and benefic properties such as antioxidant and anti-inflammatory activities. The aim of this research was to investigate a F. ornus manna extract loaded in a pectin hydrogel as a synergic vehicle to evaluate the potential use of the complex for cosmetic and dermatological applications. In particular, the study set out to disclose manna properties as a wound healing agent with antimicrobial and reparative activity on infected tissues. Moreover, considering the correlation between antioxidant activity and antiaging potential, the extract was investigated in regard to the anti-elastase activity and skin whitening potential. The total phenolic content of each extract was also determined and a safe profile by in vitro cytotoxicity studies was verified. The hydrogel complex, containing the manna extract and pectin as the gelling agent, exhibited suitable properties in terms of pH (from 5.50 to 6.80), rheological behavior and ability of preserving the antioxidant activity of the manna exudate (around 10%). All the peculiarities that make the pectin hydrogels ideal systems for skin disease, as wound dressings and for antiaging cosmetic formulations.