Exploring novel organocatalytic-acetylated pea starch blends in the development of hot-pressed bioplastics.

Acetylated starch shows enhanced thermal stability and moisture resistance, but its compatibilization with other more hydrophilic polysaccharides remains poor or unknown. In this study, the feasibility of thermomechanically compounding organocatalytically acetylated pea starch (APS), produced at two different degrees of substitution with alkanoyl groups (DSacyl, 0.39 and 1.00), with native pea starch (NPS), high (HMP) and low methoxyl (LMP) citrus pectin, and sugar beet pectin (SBP, a naturally acetylated pectin) for developing hot-pressed bioplastics was studied. Generally, APS decreased hydrogen bonding (ATR-FTIR) and crystallinity (XRD) of NPS films at different levels, depending on its DSacyl. The poor compatibility between APS and NPS or HMP was confirmed by ATR-FTIR imaging. Contrariwise, APS with DSacyl 1 was effectively thermomechanically mixed with the acetylated SBP matrix, maintaining homogeneous distribution within it (ATR-FTIR imaging). APS (any DSacyl) significantly increased the visible/UV light opacity of NPS-based films and decreased their water vapor transmission rate (WVTR, by ca. 11 %) and surface water wettability (by ca. 3 times). In comparison to NPS-APS films, pectin-APS showed higher visible/UV light absorption, tensile strength (ca.2.9-4.4 vs ca.2.4 MPa), and Young's modulus (ca.96-116 vs ca.60-70 MPa), with SBP-APS presenting significantly lower water wettability than the rest of the films.

Quality Characteristics of Raspberry Fruits from Dormancy Plants and Their Feasibility as Food Ingredients.

The raspberry (Rubus idaeus L.) is a soft red fruit consumed worldwide due to its bitter-sweet taste and phenolics-associated health benefits. During plant dormancy, raspberry fruits are discarded. However, this work hypothesised that these fruits have the chemical quality to be valorised, which would mitigate their waste if adequately stabilised. This can be achieved by drying. The Pacific Deluxe and Versailles varieties were dried by freeze- and convective-drying (30 °C and 40 °C). The freeze-dried fruits preserved their colour, drupelets structure, and phenolic content. Convective-drying promoted a significant fruit darkening, which was more evident at 30 °C due to the longer drying process, and a loss of drupelets structure. Both temperatures promoted a similar decrease in phenolic content, as determined by HPLC, although the ABTS●+ antioxidant activity at 40 °C was lower (IC50 = 9 compared to 13 µg AAE/mg dry weight). To incorporate dried raspberries into muffin formulations, while keeping their red colour, it was necessary to change the raising agent from sodium bicarbonate to baker's yeast. Sensory analysis by a non-trained panel revealed good acceptance, showing that fresh or dried raspberry fruits from dormancy had suitable characteristics for use as food ingredients.

Mycotoxins' Prevalence in Food Industry By-Products: A Systematic Review.

The recovery of biomolecules from food industry by-products is of major relevance for a circular economy strategy. However, by-products' contamination with mycotoxins represents a drawback for their reliable valorization for food and feed, hampering their application range, especially as food ingredients. Mycotoxin contamination occurs even in dried matrices. There is a need for the implantation of monitoring programs, even for by-products used as animal feed, since very high levels can be reached. This systematic review aims to identify the food by-products that have been studied from 2000 until 2022 (22 years) concerning mycotoxins' contamination, distribution, and prevalence in those by-products. PRISMA ("Preferred Reporting Items for Systematic Reviews and MetaAnalyses") protocol was performed via two databases (PubMed and SCOPUS) to summarize the research findings. After the screening and selection process, the full texts of eligible articles (32 studies) were evaluated, and data from 16 studies were considered. A total of 6 by-products were assessed concerning mycotoxin content; these include distiller dried grain with solubles, brewer's spent grain, brewer's spent yeast, cocoa shell, grape pomace, and sugar beet pulp. Frequent mycotoxins in these by-products are AFB1, OTA, FBs, DON, and ZEA. The high prevalence of contaminated samples, which surpasses the limits established for human consumption, thus limiting their valorization as ingredients in the food industry. Co-contamination is frequent, which can cause synergistic interactions and amplify their toxicity.

Potato Chips Byproducts as Feedstocks for Developing Active Starch-Based Films with Potential for Cheese Packaging.

The potato chip industry generates brownish frying residues, which are usually landfilled. While spent frying oil has value as biodiesel, the defatted brownish water-soluble extract (BrE) does not yet have an application. In this work, it was hypothesized that BrE can be a source of compounds for active packaging. BrE is composed of carbohydrates (66.9%), protein (5.7%), and a small amount of phenolics and esterified fatty acids. When incorporated into starch-based formulations and casted, BrE at 5%, 10%, and 15% w/w (dry starch weight) conferred a yellowish coloration while maintaining the transparency of neat films. The BrE increased the films' traction resistance, elasticity, and antioxidant activity while decreasing their hydrophilicity. Furthermore, starch/15% BrE-based films showed diminished water vapor and good UV-light barrier properties. Their contact with sliced cheese did not change the products' hardness during storage (14 days). Weight loss of the cheese was observed after 7 days of storage, stabilizing at 6.52%, contrary to the cheese packed in polyamide (PA)/polyethylene (PE), already used in food packaging. The cheese packed in the starch/15% BrE-based films showed a significant yellowish darkening and lower content of volatile oxidation products compared to the PA/PE. Therefore, BrE revealed to have compounds with the potential to tune the performance of starch-based films for food packaging.

Bioactive Properties of Instant Chicory Melanoidins and Their Relevance as Health Promoting Food Ingredients.

Instant chicory is a caffeine-free brew worldwide consumed as a coffee substitute. Like coffee grounds processing, chicory roots suffer a roasting process, which may lead to the formation of high-molecular weight nitrogen-brown compounds, the melanoidins. It is hypothesized that similarly to coffee, chicory melanoidins have health promoting potential. In this work, the chemical composition and biological activity of chicory high molecular weight material (HMWM) was evaluated. The chicory HMWM is composed by 28.9% (w/w) of carbohydrates, mainly fructose-rich polysaccharides (18.7% w/w) and 5.7% (w/w) of protein, distinct from coffee. The phenolic compounds constituent of the HMWM were mainly present in glycosidically linked and condensed structures (0.9 g/100 g and 5.8 g/100 g), showing in vitro ABTS•+ scavenging (IC50 = 0.28 mg/mL) and ferric ion reducing capacity (ca. 11 µg Fe2+ eq/mg). Chicory HMWM revealed to be effective against Gram-positive bacteria, mainly Staphylococcus aureus and Bacillus cereus, although not so efficient as coffee. It also showed potential to inhibit α-glucosidase activity (15% of inhibition), higher than coffee HMWM, approaching acarbose activity that is used in type 2 diabetes mellitus treatment. Thus, chicory melanoidins, when used as a food ingredient, may contribute to an antioxidant diet and to prevent diabetes, while increasing the protective effects against pathogenic bacteria.

Hydrophobic Starch-Based Films Using Potato Washing Slurries and Spent Frying Oil.

Starch is a promising candidate for preparing biodegradable films with useful gas barriers and thermoplastic capabilities. However, these materials are hydrophilic and brittle, thus limiting their application range. To overcome these drawbacks, it has been hypothesized that starch can be hydrophobized and plasticized during the starch-based film production using a single-step approach and following transesterification principles. In this work, KOH powder and spent frying oil (SFO) were used as an alkaline catalyst and a source for triacylglycerides, respectively, to promote the modification of starch. Different ratios of SFO (w/w related to the dried starch weight) were tested. When compared to the neat films (without a catalyst and SFO), the incorporation of at least 15% SFO/KOH gave rise to transparent, hydrophobic (water contact angles of ca. 90∘), stretchable (ca. 20×), elastic (ca. 5×), and water tolerant starch-based films, contrary to the films produced without the catalyst. ATR-FTIR and 1H NMR revealed structural differences among the produced films, suggesting that starch was modified with the SFO-derived fatty acids. Therefore, adding KOH during the potato starch/spent frying oil-based film's production was determined to be a promising in situ strategy to develop starch-based materials with improved hydrophobicity and flexibility, while valorizing the potato chip industry's byproducts.

Insights on Single-Dose Espresso Coffee Capsules' Volatile Profile: From Ground Powder Volatiles to Prediction of Espresso Brew Aroma Properties.

Single-dose coffee capsules have revolutionized the coffee market, fueling espresso coffee popularity and offering access to a wide selection of coffee blends. Nevertheless, scarce information related to coffee powder and brew's combined volatile characterization is available. In this study, it is hypothesized that coffee brew aroma characteristics can be predicted based on coffee powder's volatile composition. For this, headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC × GC-ToFMS) was used. The data were combined via chemometric tools to characterize in depth the volatile composition of eight blends of capsule-coffee powder and respective espresso brews, simulating the consumer's perception. A total of 390 volatile compounds were putatively identified, 100 reported for the first time in roasted coffee or brews. Although the same chemical families were determined among the coffee powders and espresso brews, a different volatile profile was determined for each matrix. The Pearson correlation of coffee powders and respective brews allowed to identify 15 volatile compounds, mainly terpenic and esters recognized by their pleasant notes, with a strong relationship between the amounts present in both matrices. These compounds can be key markers to predict the volatile aroma potential of an espresso brew when analyzing the coffee powder.

HS-SPME Gas Chromatography Approach for Underivatized Acrylamide Determination in Biscuits.

Acrylamide (AA) is a food contaminant in thermally processed products that is object of tight control. A simple and easy-to-apply methodology for routine monitoring of AA levels in food products could allow producers to be players in the control of their own products. In this work, a simple methodology for AA quantification without derivatization was developed for biscuits, for which the benchmark levels recommended by EFSA are 350 µg/kg, and 150 µg/kg for biscuits for infants and young children. Headspace-solid phase microextraction (HS-SPME) was used in 120 mL screwed-cap vials with a carboxen/polydimetylsiloxane fiber, 4 g of biscuits, and 10 mL of water during 15 min at room temperature under stirring. The addition of 30 mL of propanol under stirring during 15 min at room temperature and 15 min at 60 °C was used to promote AA transfer to the headspace. The fiber exposure was 45 min. A gas chromatography-mass spectrometry analysis allowed to obtain an external calibration curve at m/z 71, with linearity R2 > 0.99 and precision RSD < 9%. The detection and quantification limits were 27.4 µg/kg and 91.5 µg/kg, respectively. The methodology was successfully used in biscuits with lower AA amount, where mitigation strategies (asparaginase or pectate) were applied.

Characterization of Non-volatile Oxidation Products Formed from Triolein in a Model Study at Frying Temperature.

Frying allows cooking food while promoting their organoleptic properties, imparting crunchiness and flavor. The drawback is the oxidation of triacylglycerides (TAGs), leading to the formation of primary oxidized TAGs. Although they have been associated with chronic and degenerative diseases, they are precursors of pleasant flavors in fried foods. Nevertheless, there is a lack of knowledge about the oxidation species present in foods and their involvement in positive/negative health effects. In this work, high-resolution (HR) C30 reversed-phase (RP)-liquid chromatography (LC)-tandem HR mass spectrometry (MS/MS) was used to identify primary oxidation TAGs resulting from heating triolein (160 °C, 5 min). This allows simulating the initial heating process of frying oils usually used to prepare fried foods, such as chips, crisps, and snacks. Beyond hydroxy, dihydroxy, hydroperoxy, and hydroxy-hydroperoxy derivatives, already reported in phospholipids oxidized by Fenton reaction, new compounds were identified, such as dihydroxy-hydroperoxy-triolein derivatives and positional isomers (9/10- and 9/12-dihydroxy-triolein derivatives). These compounds should be considered when proposing flavor formation pathways and/or mitigating lipid-derived reactive oxygen species occurring during food frying.

Carbohydrates as targeting compounds to produce infusions resembling espresso coffee brews using quality by design approach.

All coffee brews are prepared with roasted coffee and water, giving origin to espresso, instant, or filtered coffee, exhibiting distinct physicochemical properties, depending on the extraction conditions. The different relative content of compounds in the brews modulates coffee body, aroma, and colour. In this study it was hypothesized that a coffee infusion allows to obtain extracts that resemble espresso coffee (EC) physicochemical properties. Carbohydrates (content and composition) were the target compounds as they are organoleptically important for EC due to their association to foam stability and viscosity. The freeze-drying of the extracts allowed better dissolution properties than spray-drying. Instant coffee powders were obtained with chemical overall composition resembling espresso, although with lower lipids content. The extracts were able to produce the characteristic foam through CO2 injection or salts addition. Their redissolution at espresso concentration allowed a viscosity, foamability and volatile profile representative of an espresso coffee, opening new exploitation possibilities.

Revealing the Usefulness of Aroma Networks to Explain Wine Aroma Properties: A Case Study of Portuguese Wines.

Wine aroma is the result of complex interactions between volatile compounds and non-volatile ones and individual perception phenomenon. In this work, an aroma network approach, that links volatile composition (chromatographic data) with its corresponding aroma descriptors was used to explain the wine aroma properties. This concept was applied to six monovarietal wines from Bairrada Appellation (Portugal) and used as a case study. A comprehensive determination of the wines' volatile composition was done (71 variables, i.e., volatile components), establishing a workflow that combines extraction techniques and gas chromatographic analysis. Then, a bipartite network-based approach consisting of two different nodes was built, one with 19 aroma descriptors, and the other with the corresponding volatile compound(s). To construct the aroma networks, the odor active values were calculated for each determined compound and combined with the bipartite network. Finally, the aroma network of each wine was compared with sensory descriptive analysis. The analysis of the specific aroma network of each wine revealed that Sauvignon Blanc and Arinto white wines present higher fruity (esters) and sweet notes (esters and C13 norisoprenoids) than Bical wine. Sauvignon Blanc also exhibits higher toasted aromas (thiols) while Arinto and Bical wines exhibit higher flowery (C13 norisoprenoids) and herbaceous notes (thiols), respectively. For red wines, sweet fruit aromas are the most abundant, especially for Touriga Nacional. Castelão and Touriga Nacional wines also present toasted aromas (thiols). Baga and Castelão wines also exhibit fusel/alcohol notes (alcohols). The proposed approach establishes a chemical aroma fingerprint (aroma ID) for each type of wine, which may be further used to estimate wine aroma characteristics by projection of the volatile composition on the aroma network.

A critical review on extraction techniques and gas chromatography based determination of grapevine derived sesquiterpenes.

Vitis vinifera L. (common grapevine) is considered one of the major world fruit crops based on the extent of cultivated land and on its economic value. Grapevine is composed by several different chemical compounds, including sesquiterpenic ones. Sesquiterpenic compounds play a significant role in varietal aromas, contributing to fruity and flowery odours, and are also well known for their potential health benefits. The advantages and drawbacks of different extraction and gas chromatographic techniques used for the determination of sesquiterpenic compounds are critically presented. Also, the future trends of sample preparation and gas chromatographic tools are discussed. This review provides the state-of-the-art and the technical know-how for the researchers who want to start studying sesquiterpenic compounds on complex matrices such as grapevine products.

Comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry combined with solid phase microextraction as a powerful tool for quantification of ethyl carbamate in fortified wines. The case study of Madeira wine.

An analytical methodology based on headspace solid phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC x GC-ToFMS) was developed for the identification and quantification of the toxic contaminant ethyl carbamate (EC) directly in fortified wines. The method performance was assessed for dry/medium dry and sweet/medium sweet model wines, and for quantification purposes, calibration plots were performed for both matrices using the ion extraction chromatography (IEC) mode (m/z 62). Good linearity was obtained with a regression coefficient (r(2)) higher than 0.981. A good precision was attained (R.S.D. <20%) and low detection limits (LOD) were achieved for dry (4.31 microg/L) and sweet (2.75 microg/L) model wines. The quantification limits (LOQ) and recovery for dry wines were 14.38 microg/L and 88.6%, whereas for sweet wines were 9.16 microg/L and 99.4%, respectively. The higher performance was attained with sweet model wine, as increasing of glucose content improves the volatile compound in headspace, and a better linearity, recovery and precision were achieved. The analytical methodology was applied to analyse 20 fortified Madeira wines including different types of wine (dry, medium dry, sweet, and medium sweet) obtained from several harvests in Madeira Island (Portugal). The EC levels ranged from 54.1 microg/L (medium dry) to 162.5 microg/L (medium sweet).