The effect of extraction solvents (30, 50 and 70 % aqueous solutions of ethanol and acetone, and 100 % distilled water), extraction temperature (60 and 90°C) and extraction time (30, 60 and 90 min) ...on the composition and mass fraction of polyphenolic compounds in Dalmatian wild sage (Salvia officinalis L.) extracts has been investigated. The total polyphenolic content of sage extracts was determined spectrophotometrically using Folin-Ciocalteu method, whereas the individual polyphenols were determined by HPLC UV/PDA method. Results indicated that the main polyphenols in sage extracts were vanillic, caffeic, syringic, salvianolic K and salvianolic I acids, methyl rosmarinate, 6-hydroxyluteolin-7-glucoside, luteolin-7-glucuronide, luteolin-7-glucoside, apigenin-7-glucunoride, apigenin-7-glucoside, with rosmarinic acid and luteolin-3-glucuronide as predominant compounds. The mass fractions of total and individual polyphenols significantly depend on the type of extraction solvent, solvent composition and extraction temperature. The results showed that binary solvent systems are more efficient than mono-solvent systems in the extraction of polyphenolic compounds in regard to their relative polarity. The aqueous solutions of ethanol or acetone (30 %), extraction temperature of 60°C and extraction time of 30 min were the most efficient for the extraction of polyphenols from dry sage leaves. Key words: sage, phenolic acids, flavone glycosides, extraction parameters
•Cultivation had no significant effect on anthocyanin content.•Cultivar and processing significantly influenced anthocyanin content.•Processing purees to jams decreased anthocyanins content for ...28%.•ΔE∗ab significantly increased with processing to jams.•Color parameters are strongly correlated with content of anthocyanins.
The objective of this study was to detect influences of cultivar, cultivation and processing on anthocyanin content and color in purees and low-sugar jams produced from strawberry cultivars (Elsanta, Maya, Marmolada, Queen Elisa), grown under conventional and organic cultivation. Color was determined by CIELab values while anthocyanins were quantified by HPLC-UV/VIS-PDA. Queen Elisa was the best cultivar for processing as it had highest total anthocyanin content (TAC) that was well preserved in processing. On average, processing purees to jams decreased TAC for 28% where pelargonidin-3-glucoside revealed most noticeable loss (53%) and cyanidin-3-rutinoside was best preserved in processing. Obtained results indicated that measurement of colorimetric parameters are strongly correlated with content of anthocyanins. In other words, loss of anthocyanins during processing was accompanied by noticeable decrease in lightness, red/yellow color and total color change. Results showed that change of color is useful predictor for estimating anthocyanins in strawberry purees and jams.
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► HPCD partially inactivated the natural microbial flora and enzymes in fresh-cut carrot. ► Bioactive compounds and antioxidant capacity of the samples were preserved. ► 90% texture ...reduction was observed for the samples treated at 12MPa, 40°C, 15min. ► HPCD did not seem to be feasible as innovative technique to pasteurize fresh-cut carrot.
High pressure carbon dioxide treatment (HPCD) was applied for the pasteurization of fresh-cut carrot. The inactivation kinetics of the natural microbial flora were determined as a function of the treatment conditions (8 or 12MPa, 22, 35, 40, 45°C, 5–45min) to investigate the more feasible process conditions to assure a microbial stability to the product. Further, the effect of HPCD treatment on the qualitative aspects of the product in terms of enzymatic activity (polyphenol oxidase (PPO), peroxidase (POD), pectin methylesterase (PME) and polygalacturonase (PG)), bioactive composition (phenol, flavonoid, carotenoid, ascorbic acid content and antioxidant capacity), texture, pH and tritatable acidity (TA) were measured. A storage study at refrigerated conditions (4°C) for 4 weeks was also performed to monitor the microbial and qualitative stability of the product. The results showed that 12MPa, 40°C, 15min were effective to inactivate the natural microbial flora and assure the microbial and enzymatic stability of the product for 4 weeks. Bioactive compounds content, antioxidant capacity, and enzyme stability were all preserved with the exception of the texture which exhibited a significant reduction up to 90% compared to the control, and the ascorbic acid content which was reduced down to 40%.
Recently, natural plant extracts have been used to increase the nutritional value of food and to potentially reduce the absorbed fat and the formation of acrylamide in fried foods. Literature data on ...the use of edible polymers with nettle or olive leaf extracts are scarce.
The effect of novel coatings on colour, fat absorption, phenolic and sugar content, and acrylamide formation in deep-fat-fried fresh-cut potatoes was evaluated. Extracts of olive and nettle leaves were incorporated in carboxymethyl cellulose (CMC) and gum arabic, used as coatings for potatoes and applied before frying. This aimed to improve the nutritional quality of deep-fat-fried fresh-cut potatoes.
Enrichment of the edible coatings with extracts resulted in a significant change in the visible colour of the potatoes before frying. Significant effect of the extract amount on the sensory characteristics of potatoes was also observed. Most importantly, the perception of characteristic potato odour and taste was not significantly affected by the coating. Although higher amounts of the extract (1.5%) resulted in higher phenolic mass fraction in fried potatoes, the sensory scores decreased. After frying, fat mass fraction in the coated potatoes was reduced by about 15% compared to the uncoated samples. The type of extract affected the total sugar mass fraction in fried potatoes, which was lower in the samples with coatings enriched with olive leaf than in those with nettle leaf. Only gum arabic coating had a reducing effect on acrylamide mass fraction by 17%. Based on all the obtained results, CMC and gum arabic coatings did not influence sensory properties, so they can be recommended as carriers of functional compounds or as a frying pre-treatment for potatoes with favourable effect on fat and acrylamide content.
The knowledge obtained in this study can be exploited for preparation of coatings with functional compounds used as a pre-treatment for fried food with favourable effect on fat and acrylamide content.
Research background. Potato tissue is damaged during fresh-cut production, which makes fresh-cut potato susceptible to the quality loss and microbiological spoilage. At the same time, such products ...are desirable due to their convenience; however, they are extremely sensitive and have short shelf life. The main challenge of the fresh-cut potato industry is to find possibilities to overcome these drawbacks. UV-C treatment, known for its antibacterial activity, is a promising technique and it shows a potential to improve shelf life of fresh-cut potato products.
Experimental approach. The influence of the UV-C treatment on the safety and quality, as well as sensory traits of fresh-cut potato (Solanum tuberosum L. cv. Birgit) during storage was examined. For this purpose, 0-, 3-, 5- and 10-min UV-C irradiation was applied on vacuum-packed potato slices pretreated with sodium ascorbate solution. During 23 days of storage at (6±1) °C, microbiological, physicochemical and sensory properties of raw samples were monitored, along with sensory properties of boiled and fried fresh-cut potatoes.
Results and conclusions. The 5- and 10-min UV-C treatments significantly reduced microbial growth, increased total solids and lightness (L*), and positively affected odour and firmness of raw potatoes. Cooked UV-C-treated samples were described with more pronounced characteristic potato odour and taste. Overall, UV-C-treated fresh-cut potato retained its good quality and sensory traits up to 15 days at (6±1) °C.
Novelty and scientific contribution. To the best of our knowledge, this is the first scientific article dealing with the effect of UV-C light on durability (safety, quality and sensory traits) of fresh-cut potato cv. Birgit and its suitability for boiling and frying. In general, UV-C treatment is a known antimicrobial technique, but its application on fresh-cut potato is poorly explored. Results confirmed that vacuum-packed fresh-cut potato treated only with UV-C and sodium ascorbate as anti-browning agent, without the addition of chemical preservatives, had twofold longer shelf-life at (6±1) °C than the fresh-cut potato not treated with UV-C. Fresh-cut potato treated with UV-C retained good overall quality and sensory properties either raw, boiled or fried. Results of this study could also be useful for producers in terms of potential UV-C application as a strategy for prolonging the shelf-life of fresh-cut potato.
Objectives in this study were to model/predict simultaneous influences of apple O2‐consumption/CO2‐production rates
(RO2/CO2) and modified atmosphere packaging (MAP) (from volumetric concentrations ...of O2/CO2
(yO2/CO2)on microbial growth (Aerobic mesophilic bacteria, AMB; Enterobacteriaceae, EBac) in 2 fresh‐cut apple cultivars treated with five anti‐browning treatments and stored in refrigerator. Growth of both microorganisms was best predicted by length of shelf‐life,
RO2/CO2, and yO2/CO2.With AMB/EBac growth, cultivar's
RO2 decreased together with
yO2 in packaging. Similarly, with microbial growth
RCO2 dropped, while simultaneously
yCO2increase was observed in package. Regression coefficients ratios for AMB‐respiration models were similar to ratios for stoichiometric coefficients for respiration equation with malic acid as main substrate. Hence, presented models likely captured natural relations between predictors, and gave good estimate of AMB growth and its association with respiration in MAP. Apple browning had weak or no association with bacterial growth. Obtained models may be utilized to optimize industrial parameters with least AMB/EBac growth, hence facilitate extension of fresh‐cut apple shelf‐life.
Practical Applications
Relationships between fresh‐cut apples O2‐consumption/CO2‐production rates, volumetric concentrations of O2/CO2 in modified atmosphere packaging (MAP) and microbial growth (Aerobic mesophilic bacteria, AMB; Enterobacteriaceae EBac) were established and yielded mathematical models which may be utilized to optimize industrial parameters with least AMB/EBac growth, hence facilitate extension of fresh‐cut apple shelf‐life. All equations and models are publicly accessible at apple.pbf.hr or 31.147.204.87, and can be used to calculate almost every parameter relevant for apple respiration and apple browning (only for permeable systems). Additionally, users can choose their own production settings (size of package, initial volumetric concentration of gases, apple mass), and calculate optimal values (with least browning) for their fresh‐cut processes (taking into account their own packaging film and others). Therefore, results presented in this paper will likely be useful to the fresh‐cut industry.
The aim of this work was to investigate the influence of olive type (green and black) and content on quality and sensory properties of spreadable cheese with olives. Total solids, pH value, colour ...(colourimetric), total phenols by Folin-Ciocalteau method and antioxidant capacity (FRAP) of the raw materials as well as of the prepared samples were examined. Furthermore, samples of spreadable cheese with olives were sensory evaluated using the Quantitative Descriptive Analysis (QDA). ANOVA showed that the applied sources of variation significantly affected the majority of investigated parameters. Samples with black olives had slightly higher dry matter content and pH value, and were characterized by darker and dull colour. The determined total phenols contents and antioxidant capacity showed a good potential of spreadable cheese with olives as a functional food, whereby green olives samples had higher total phenols content as well as
antioxidant capacity. Generally, sensory properties of all samples were
very well scored, indicating their good acceptability by consumers. Samples with black olives accomplished higher scores for flavour harmony
and overall acceptability, where spreadable cheese with the highest olive content emphasized with the highest scores for these properties.
Cilj ovog rada bio je ispitati utjecaj tipa (crne i zelene) i udjela masline na kvalitetu i senzorska svojstva sirnog namaza s maslinama. U uzorcima polaznih sirovina te pripremljenog sirnog namaza s maslinama određeni su ukupna suha tvar, pH vrijednost, boja (kolorimetrijski), sadržaj ukupnih fenola Folin-Ciocalteau metodom i antioksidacijski kapacitet (FRAP). Nadalje, uzorci sirnog namaza senzorski su ocijenjeni kvantitativnom deskriptivnom analizom (QDA). ANOVA je pokazala da su primijenjeni izvori varijacija značajno utjecali na većinu ispitivanih parametara. Uzorci s crnim maslinama imali su nešto viši udio suhe tvari, pH vrijednost te tamniju i zasićeniju boju. Određeni sadržaj ukupnih fenola i antioksidacijski kapacitet ukazuju na dobar potencijal sirnog namaza s maslinama kao funkcionalne hrane, gdje su uzorci sa zelenim maslinama sadržavali više ukupnih fenola i antioksidacijski kapacitet. Općenito, senzorska svojstva svih uzoraka su vrlo dobro ocijenjena, što upućuje na njihovu dobru prihvatljivost kod potrošača. Uzorci s crnim maslinama postigli su više ocjene za harmoničnost arome i
ukupnu prihvatljivost, gdje se uzorak sirnog namaza s najvišim udjelom maslina istaknuo najvišim ocjenama za navedena svojstva.
The effect of anti-insect photoselective yellow (mesh size of 2.4x4.8 mm) and Stop Drosophila Normal (mesh size of 0.90x1 mm) nets on the generative and vegetative traits of peach (cv. Suncrest) was ...studied at an orchard near the city of Čakovec, Croatia. Netting significantly affected some vegetative parameters (leaf surface, leaf length and leaf shape index) but there was no significant effect on productivity parameters (yield, yield efficiency, fruit mass and share of decayed fruit). Regarding fruit colouration application of nets significantly affected b* and C* background and L*, b*, C* and h° additional colour parameters. Majority of inner fruit quality parameters (fruit firmness, titratable acidity and total soluble solids / titratable acidity ratio) as well as of bioactive compounds (total polyphenolic content, antioxidant activity, anthocyanin content and share of alkali-soluble pectin) was also under significant effect of netting. Since yellow net only slightly reduced peach fruit quality (compared to control) it can be recommended for application as an anti-insect net. However, Stop Drosophila Normal net more notably reduced quality parameters (especially additional fruit colour) and hence should be used only when other control strategies show to be ineffective.
UV-C irradiation successfully reduces the growth of microorganisms, but it can also affect the content of phenolics and sugars of fresh-cut potatoes (FCP). This could consequently alter antioxidant ...capacity of FCP or its potential for acrylamide formation. Therefore, this paper investigates the influence of UV-C irradiation on the content of phenolics chlorogenic acid (CA) and individual sugars during storage of FCP as well as after cooking. Acrylamide was also monitored in FCP after frying. Potato slices pre-treated with sodium ascorbate solution and vacuum-packaged were UV-C irradiated for 0, 3, 5, and 10 min in order to obtain irradiation doses of 0, 1.62, 2.70, and 5.40 kJ m−2, respectively, stored for 23 days (+6 °C), and subsequently boiled and fried. As the applied dose and storage duration increased, the CA content in raw FCP decreased (it retained for 75.53–88.34%), while the content of sugars as well as acrylamide in fried FCP increased. Although the increase was the most noticeable at the applied dose of 2.70 kJ m−2, the acrylamide content was always below proposed limit. Boiling and frying reduced the content of CA and sugars. In spite of certain alterations, applied doses of irradiation can ensure acceptable product in regard to phenolics and sugars, and acrylamide content particularly.
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