Effect of different baking treatments on the acrylamide formation and phenolic compounds in Californian-style black olives

Advancements in Chemical and Biosensors for Point-of-Care Detection of Acrylamide

Acrylamide (AA), an odorless and colorless organic small-molecule compound found generally in thermally processed foods, possesses potential carcinogenic, neurotoxic, reproductive, and developmental toxicity. Compared with conventional methods for AA detection, bio/chemical sensors have attracted much interest in recent years owing to their reliability, sensitivity, selectivity, convenience, and low cost. This paper provides a comprehensive review of bio/chemical sensors utilized for the detection of AA over the past decade. Specifically, the content is concluded and systematically organized from the perspective of the sensing mechanism, state of selectivity, linear range, detection limits, and robustness. Subsequently, an analysis of the strengths and limitations of diverse analytical technologies ensues, contributing to a thorough discussion about the potential developments in point-of-care (POC) for AA detection in thermally processed foods at the conclusion of this review.

Electronic Prediction of Chemical Contaminants in Aroma of Brewed Roasted Coffee and Quantification of Acrylamide Levels

The aim of this research was to apply an electronic device as indirect predictive technology to evaluate toxic chemical compounds in roasted espresso coffee. Fresh coffee beans were subjected to different thermal treatments and analyzed to determine volatile organic compounds, content of acrylamide and 5-hydroxymethylfurfural, sensory characteristics and electronic nose data. In total, 70 different volatile compounds were detected and grouped into 15 chemical families. The greatest percentage of these compounds were furans, pyrazines, pyridines and aldehydes. The positive aroma detected had the intensity of coffee odor and a roasted aroma, whereas the negative aroma was related to a burnt smell. A linear relationship between the toxic substances and the sensory defect was established. A high sensory defect implied a lower content of acrylamide and a higher content of 5-hydroxymethylfurfural. Finally, electronic signals were also correlated with the sensory defect. This relationship allowed us to predict the presence of these contaminants in the roasted coffee beverage with an indirect method by using this electronic device. Thus, this device may be useful to indirectly evaluate the chemical contaminants in coffee beverages according to their sensory characteristics.

Effect of elaboration process, crop year and irrigation on acrylamide levels of potential table olive varieties

BACKGROUND

Table olives are widely consumed in the Mediterranean diet, and several typical Spanish and Portuguese varieties could potentially be used as such. In order to ensure a good-quality product, the effect of different factors such as elaboration processes, irrigation conditions, crop year and their crossover interaction on acrylamide content and antioxidant compounds needs to be deeply studied.

RESULTS

When looking through irrigation, regulated deficit irrigation (RDI) presented lower acrylamide levels than rainfed conditions for 'Cordovil de Elvas', 'Picual' and 'Verdeal Alentejana'. No significant interactions were found between the type of irrigation and elaboration style for 'Arbequina' and 'Koroneiki' varieties. Although RDI had the largest concentration of total phenols, antioxidant activity was also the highest. The table olives harvested in the crop year of 2019 showed lower levels of acrylamide due to a significant relationship between the crop year and irrigation conditions.

CONCLUSIONS

Novel varieties to be marketed should be taken into consideration for table olive elaboration. The impact of the crop year on the bioactive value of table olives and crossover interactions relies strongly in climatological conditions. Last but not least, the benefit of selecting the best irrigation and elaboration methods is crucial to ensure desirable acrylamide levels. © 2023 Society of Chemical Industry.

New and Rapid Analytical Method Using HPLC-MS Detection for Acrylamide Determination in Black Ripe Olives

The presence of acrylamide, a known human carcinogen, in various heated foods raises significant concerns among consumers. Therefore, the development of a good analytical method is of paramount interest to the scientific community. Keeping this in view, a rapid, simple, reliable, and low-cost analytical method was developed and validated for acrylamide quantification in black ripe olives. The method consisted of the water extraction of the compounds from crushed olives with the addition of (13C3)acrylamide as an internal standard. The quantification was performed using high-pressure liquid chromatography and mass detection with positive electrospray ionization. The limits of detection and quantification were determined to be 4 and 11 µg/kg, respectively. The developed method exhibited excellent results in terms of accuracy (98.4-104.8%) and intra- and inter-day precision limits, both less than 20%. This new method was carried out by analyzing 15 samples of Spanish commercial black ripe olives, revealing a wide range of values, from 79 to 1068 µg/kg of fruit. The new protocol reduces the analysis time to just one hour per sample versus the minimum 24 h required by gas chromatography and mass detection, meaning that it could be a good option for the routine analysis of acrylamide in black ripe olives, and may be extendable to the analysis of this compound in other foods.

Enrichment of Cookies with Fruits and Their By-Products: Chemical Composition, Antioxidant Properties, and Sensory Changes

Cookies made from wheat have become increasingly popular as a snack due to their various advantages, such as their convenience as a ready-to-eat and easily storable food item, wide availability in different types, and affordability. Especially in recent years, there has been a trend towards enriching food with fruit additives, which increase the health-promoting properties of the products. The aim of this study was to examine current trends in fortifying cookies with fruits and their byproducts, with a particular focus on the changes in chemical composition, antioxidant properties, and sensory attributes. As indicated by the results of studies, the incorporation of powdered fruits and fruit byproducts into cookies helps to increase their fiber and mineral content. Most importantly, it significantly enhances the nutraceutical potential of the products by adding phenolic compounds with high antioxidant capacity. Enriching shortbread cookies is a challenge for both researchers and producers because the type of fruit additive and level of substitution can diversely affect sensory attributes of cookies such as color, texture, flavor, and taste, which have an impact on consumer acceptability.

Accumulation of Antioxidative Phenolics and Carotenoids Using Thermal Processing in Different Stages of Momordica charantia Fruit

The bitter taste of M. charantia fruit limits its consumption, although the health benefits are well known. The thermal drying process is considered as an alternative method to reduce the bitterness. However, processing studies have rarely investigated physiochemical changes in fruit stages. The antioxidant activities and physiochemical properties of various fruit stages were investigated using different thermal treatments. The color of the thermally treated fruit varied depending on the temperature. When heat-treated for 3 days, the samples from the 30 °C and 90 °C treatments turned brown, while the color of the 60 °C sample did not change significantly. The antioxidant activities were increased in the thermally processed samples in a temperature-dependent manner, with an increase in phenolic compounds. In the 90 °C samples, the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity presented a 6.8-fold higher level than that of nonthermal treatment in mature yellow fruit (S3), whereas the activity showed about a 3.1-fold higher level in immature green (S1) and mature green (S2) fruits. Regardless of the stages, the carotenoid content tended to decrease with increasing temperature. In terms of antioxidant activities, these results suggested that mature yellow fruit is better for consumption using thermal processing.

Allicin Promoted Reducing Effect of Garlic Powder through Acrylamide Formation Stage

Background: Acrylamide is formed during food heating and is neurotoxic to animals and potentially carcinogenic to humans. It is important to reduce acrylamide content during food processing. Researchers have suggested that garlic powder could reduce acrylamide content, but the key substance and acrylamide reduction pathway of garlic powder was unclear. Methods: The inhibitory effect of garlic powder on acrylamide in asparagine/glucose solution and a fried potato model system were firstly evaluated. Furthermore, the effect of allicin on the amount of produced acrylamide in the asparagine/glucose solution model system and fried potatoes was studied with kinetic analysis. Results: The freeze-dried garlic powder had a higher inhibition rate (41.0%) than oven-dried garlic powder (maximum inhibition rate was 37.3%), and allicin had a 71.3% attribution to the reduction of acrylamide content. Moreover, the inhibition rate of allicin had a nonlinear relationship with the addition level increase. The kinetic analysis indicated that garlic powder and allicin could reduce acrylamide content through the AA formation stage, but not the decomposition stage. Conclusions: Allicin was the key component of garlic powder in reducing acrylamide content during acrylamide formation stage. This research could provide a new method to reduce acrylamide content during food processing and expand the application area of garlic.

Masking Effect of Cassia grandis Sensory Defect with Flavoured Stuffed Olives

Carao (Cassia grandis) is an America native plant characterized by its high iron content. This particular property allows its use as a natural additive to fix the black colour in California-style black olives, while masking its unpleasant aroma by stuffing olives with flavoured hydrocolloid. The tasting panel evaluated olives filled with unflavoured hydrocolloid with a fruity aroma, classified them as an extra category. Olives with the Carao addition presented a positive aroma, but also showed negative sensory attributes such as cheese, fermented and metallic flavours/aromas. The aroma of lyophilized Carao was better than the fresh one. The ‘Mojo picón’ aroma masked defective olives, allowing their classification from the second to the first commercial category. The volatile compounds belonged to the following families: terpenes, hydrocarbons, and oxygenated compounds, while the minor ones were alcohols and acid derivatives. The main volatile compounds identified were dialyl disulphide and 3-methyl-butanoic acid; among the minor ones were 2,4-dimethyl-hexane and dimethyl-silanediol and nonanal. Addition of fresh Carao increased the unpleasant aroma provoked by 3-methyl-butanoic acid, 2-methyl-butanoic acid and (E)-2-Decenal. Finally, an electronic device was able to discriminate these aromas and the results obtained agreed with those of the tasting panel and the volatile compounds.

Electronic nose application for the discrimination of sterilization treatments applied to Californian-style black olive varieties

BACKGROUND

Olive oil continues to be the main destination for olives. The production of table olives is increasing. 'Californian-style' processes are among the most frequently employed to produce oxidized olives. Sensory evaluation requires the development of an instrumental detection method that can be used as an adjunct to traditional tasting panels.

RESULTS

An electronic nose (E-nose) was used to classify two varieties of olives following exposure to different sterilization. Principal component analysis (PCA) revealed that both varieties had different volatile profiles. Sensory panel evaluations were similar for both. Partial least squares-discriminant analysis (PLS-DA) obtained from the E-nose was able to separate the two varieties and explained 82% of total variance. Moreover, volatile profiles correctly classified olives according to sterilization times recorded up to 121 °C . The only exception was at F₀  ≥ 22 min, at which a plot of PCA outcomes failed to differentiate scores. E-nose data showed similar results to those produced from the volatile analysis when grouping samples were sterilized to F₀  ≥ 18 min, at the same time distinguishing these samples from those subjected to less intense thermal treatments. A partial least squares (PLS) chemometric approach was evaluated for quantifying important olive quality parameters. With regards to validation parameters, R P 2 pertaining to perceived defect was 0.88, whilst R P 2 pertaining to overall assessment was 0.78.

CONCLUSIONS

E-nose offers a fast, inexpensive and non-destructive method for discriminating between varieties and thermal treatments up to a point at which cooking defects are highly similar (from F₀  = 18 onwards). © 2021 Society of Chemical Industry.

Characterization of Polyphenol and Volatile Fractions of Californian-Style Black Olives and Innovative Application of E-nose for Acrylamide Determination

Californian-style black olives require a sterilization treatment that produces a carcinogenic contaminant, acrylamide. Thus, this compound was evaluated in two different olive cultivars using an electronic nose (E-nose). The sterilization intensity had a significant influence on the final phenol concentrations, acrylamide content, and volatile compounds. Increasing the sterilization intensity from 10 to 26 min (F0) reduced the phenol content, but it promoted acrylamide synthesis, leading to a wide range of this toxic substance. The Ester and phenol groups of volatile compounds decreased their content when the sterilization treatment increased; however, aldehyde and other volatile compound groups significantly increased their contents according to the thermal treatments. The compounds 4-ethenyl-pyridine, benzaldehyde, and 2,4-dimethyl-hexane are volatile compounds with unpleasant odours and demonstrated a high amount of influence on the differences found after the application of the thermal treatments. The “Manzanilla Cacereña” variety presented the highest amount of phenolic compounds and the lowest acrylamide content. Finally, it was found that acrylamide content is correlated with volatile compounds, which was determined using multiple linear regression analysis (R² = 0.9994). Furthermore, the aroma of table olives was analysed using an E-nose, and these results combined with Partial Least Square (PLS) were shown to be an accurate method (range to error ratio (RER) >10 and ratio of performance to deviation (RPD) >2.5) for the indirect quantification of this toxic substance.

Quality Formation of Adzuki Bean Baked: From Acrylamide to Volatiles under Microwave Heating and Drum Roasting

Baked adzuki beans are rich in tantalizing odor and nutritional components, such as protein, dietary fiber, vitamin B, and minerals. To analyze the final quality of baked beans, the acrylamide and volatile formation of adzuki beans were investigated under the conditions of microwave baking and drum roasting. The results indicate that the acrylamide formation in baked adzuki beans obeys the exponential growth function during the baking process, where a rapid increase in acrylamide content occurs at a critical temperature and low moisture content. The critical temperature that leads to a sudden increase in acrylamide content is 116.5 °C for the moisture content of 5.6% (w.b.) in microwave baking and 91.6 °C for the moisture content of 6.1% (w.b.) in drum roasting. The microwave-baked adzuki beans had a higher formation of the kinetics of acrylamide than that of drum-roasted beans due to the microwave volumetric heating mode. The acrylamide content in baked adzuki beans had a significant correlation with their color due to the Maillard reaction. A color difference of 11.1 and 3.6 may be introduced to evaluate the starting point of the increase in acrylamide content under microwave baking and drum roasting, respectively. Heating processes, including microwave baking and drum roasting, for adzuki beans generate characteristic volatile compounds such as furan, pyrazine, ketone, alcohols, aldehydes, esters, pyrroles, sulfocompound, phenols, and pyridine. Regarding flavor formation, beans baked via drum roasting showed better flavor quality than microwave-baked beans.

Acrylamide in Bakery Products: A Review on Health Risks, Legal Regulations and Strategies to Reduce Its Formation

Acrylamide is a contaminant as defined in Council Regulation (EEC) No 315/93 and as such, it is considered a chemical hazard in the food chain. The toxicity of acrylamide has been acknowledged since 2002, among its toxicological effects on humans being neurotoxicity, genotoxicity, carcinogenicity, and reproductive toxicity. Acrylamide has been classified as carcinogenic in the 2A group, with human exposure leading to progressive degeneration of the peripheral and central nervous systems characterized by cognitive and motor abnormalities. Bakery products (bread, crispbread, cakes, batter, breakfast cereals, biscuits, pies, etc.) are some of the major sources of dietary acrylamide. The review focuses on the levels of acrylamide in foods products, in particular bakery ones, and the risk that resulting dietary intake of acrylamide has on human health. The evolving legislative situation regarding the acrylamide content from foodstuffs, especially bakery ones, in the European Union is discussed underlining different measures that food producers must take in order to comply with the current regulations regarding the acrylamide levels in their products. Different approaches to reduce the acrylamide level in bakery products such as the use of asparginase, calcium salts, antioxidants, acids and their salts, etc., are described in detail.

Industrial Strategies to Reduce Acrylamide Formation in Californian-Style Green Ripe Olives

Acrylamide, a compound identified as a probable carcinogen, is generated during the sterilization phase employed during the processing of Californian-style green ripe olives. It is possible to reduce the content of this toxic compound by applying different strategies during the processing of green ripe olives. The influence of different processing conditions on acrylamide content was studied in three olives varieties (“Manzanilla de Sevilla”, “Hojiblanca”, and “Manzanilla Cacereña”). Olives harvested during the yellow–green stage presented higher acrylamide concentrations than green olives. A significant reduction in acrylamide content was observed when olives were washed with water at 25 °C for 45 min (25% reduction) and for 2 h (45% reduction) prior to lye treatment. Stone olives had 21–26% higher acrylamide levels than pitted olives and 42–50% higher levels than sliced olives in the three studied varieties. When calcium chloride (CaCl₂) was added to the brine and brine sodium chloride (NaCl) increased from 2% to 4%, olives presented higher concentrations of this contaminant. The addition of additives did not affect acrylamide levels when olives were canned without brine. Results from this study are very useful for the table olive industry to identify critical points in the production of Californian-style green ripe olives, thus, helping to control acrylamide formation in this foodstuff.

Review of Research into the Determination of Acrylamide in Foods

Acrylamide (AA) is produced by high-temperature processing of high carbohydrate foods, such as frying and baking, and has been proved to be carcinogenic. Because of its potential carcinogenicity, it is very important to detect the content of AA in foods. In this paper, the conventional instrumental analysis methods of AA in food and the new rapid immunoassay and sensor detection are reviewed, and the advantages and disadvantages of various analysis technologies are compared, in order to provide new ideas for the development of more efficient and practical analysis methods and detection equipment.

Monitoring of acrylamide and phenolic compounds in table olive after high hydrostatic pressure and cooking treatments

Acrylamide and phenolic compounds on both fresh and cooked olives were monitored by HPLC/MS-MS and reversed-phase-HPLC methods along different procedures: elaboration process, high hydrostatic pressure (HHP), cooking treatment and bioavailability evaluation. Acrylamide was not detected during the elaboration process and after HHP treatment. Hydroxytyrosol, tyrosol, oleuropein and verbascoside were the most important phenols after HHP treatment. The frying and baking processes on olives enhanced the formation of acrylamide and a significant reduction in the phenolic compounds. The frying process produced lower acrylamide concentration and less reduction of phenolic compounds than the baking process, while in the gastrointestinal digestion these compounds were slightly reduced if compared to the initial stage. As a conclusion, the best way to ingest high quantities of phenols and reduce acrylamide consumption is by ingesting the olives when they are fresh. In case the olives need to be cooked, specific time and temperature conditions shall be applied.