Annalisa Mentana

EAT-by-LIGHT: Fiber-Optic and Micro-Optic Devices for Food Quality and Safety Assessment

A selection is presented of fiber-optic and micro-optic devices that have been designed and tested for guaranteeing the quality and safety of typical foods, such as extra virgin olive oil, beer, and milk. Scattered colorimetry is used to authenticate various types of extra virgin olive oil and beer, while a fiber-optic-based device for UV-VIS-NIR absorption spectroscopy is exploited in order to obtain the hyperspectral optical signature of olive oil. This is done not only for authentication purposes, but also so as to correlate the spectral data with the content of fatty acids, which are important nutritional factors. A micro-optic sensor for the detection of olive oil aroma that is capable of distinguishing different ageing levels of extra virgin olive oil is also presented. It shows effective potential for acting as a smart cap of bottled olive oil in order to achieve a nondestructive olfactory perception of oil ageing. Lastly, a compact portable fluorometer for the rapid monitoring of the carcinogenic M1 aflatoxin in milk, is experimented.

Differential Expression of Durum Wheat Gluten Proteome under Water Stress during Grain Filling.

Environmental stress during grain filling may affect wheat protein composition, thus influencing its final quality. A proteomic approach was used to evaluate changes in storage protein composition under water stress of two Italian durum wheat (Triticum turgidum ssp. durum) cultivars, Ciccio and Svevo. The high-molecular-weight glutenin region increased progressively in both cultivars and under two water regimens. The L48-35 region, corresponding to low-molecular-weight (LMW) glutenin subunits, increased slightly during grain development and decreased under water stress in both cultivars. In particular, an s-type LMW related to superior technological quality was down-expressed in the early-mid period in Svevo and in the mid-late period in Ciccio. Finally, the L<35 region, corresponding to gliadin-like proteins, decreased slightly during grain development and increased under stress in both cultivars. Several α-gliadins, associated with immunological potential, increased their expression under water stress, especially in Svevo in the early-mid stage of grain filling.

The effect of in-amphorae aging on oenological parameters, phenolic profile and volatile composition of Minutolo white wine

A wine was obtained from cryomacerated Minutolo grapes under reductive conditions and aged for 12months in glass container and in 3 types of amphorae. After aging, wines in glass containers showed the highest alcohol content, volatile acidity, dissolved oxygen, concentrations of aromatics, alcohols, and esters and by the lowest contents of enols and terpenes. They also showed the highest decrease of flavonoids, hydroxycinnamoyl tartaric acids, and procyanidins. Wines in raw amphorae showed the dramatic decrease of flavonoids and flavans reactive with vanillin. The highest antioxidant activity was exhibited by wines in engobe amphorae, while the lowest values were showed by the wines in glass containers and glazed amphorae. Caftaric acid and procyanidin B3 decreased in wine aged under glass while epicatechin mainly reduced in raw amphorae. According to the Principal Component Analysis, the wines resulted homogeneously grouped as a function of the type of container in which were aged.

Microbial cell-free extracts affect the biochemical characteristics and sensorial quality of sourdough bread

This study aimed to improve the sensorial quality of sourdough wheat bread by the addition of cell-free enzyme extracts (CFEs) from Lactobacillus sanfranciscensis (SF), Hafnia alvei (HF) and Debaryomyces hansenii (DH). CFEs were suitable sources of peptidases, glutamate dehydrogenase and cystathionine γ-lyase. The concentration of free amino acids (FAA) in the sourdoughs containing CFEs was higher than the control sourdough, produced without addition of CFEs. The community-level catabolic profiles showed that the highest number of carbohydrates, polymers and carboxylic acids were consumed in the SF sourdough. Breads produced with CFEs were characterized by higher specific volume than the control. The use of CFEs impacted on the profile of volatile organic compounds. Overall, positive correlations were found between some key-aroma compounds and enzyme activities/precursor FAA. The SF bread, characterized by highest level of alcohols, received the highest score for aroma and sweetness in the sensory analysis.

EAT-by-LIGHT fiber-optic and micro-optic devices for food quality and safety assessment

A selection is presented of fiber-optic and micro-optic devices that have been designed and tested for guaranteeing the quality and safety of typical foods, such as extra virgin olive oil, beer, and milk. Scattered colorimetry is used to authenticate various types of extra virgin olive oil and beer, while a fiber-optic-based device for UV-VIS-NIR absorption spectroscopy is exploited in order to obtain the hyperspectral optical signature of olive oil. This is done not only for authentication purposes, but also so as to correlate the spectral data with the content of fatty acids, which are important nutritional factors. A micro-optic sensor for the detection of olive oil aroma that is capable of distinguishing different ageing levels of extra virgin olive oil is also presented. It shows effective potential for acting as a smart cap of bottled olive oil in order to achieve a non-destructive olfactory perception of oil ageing. Lastly, a compact portable fluorometer for the rapid monitoring of the carcinogenic M1 aflatoxin in milk, is experimented.

Quality monitoring of extra-virgin olive oil using an optical sensor

An optical sensor for the detection of olive oil aroma is presented. It is capable of distinguishing different ageing levels of extra-virgin olive oils, and shows effective potential for achieving a non destructive olfactory perception of oil ageing. The sensor is an optical scanner, fitted with an array of metalloporphyrin-based sensors. The scanner provides exposure of the sensors to the flow of the oil vapor being tested, and their sequential spectral interrogation. Spectral data are then processed using chemometric methodologies.

Volatile composition and sensory profile of wines obtained from partially defoliated vines: the case of Nero di Troia wine

The effects of defoliation treatments performed in the bunch-zone on volatile composition and sensory attributes of the corresponding wines were evaluated. Nero di Troia grapes were subjected to four different treatments: no leaf removal (N); leaf removal in the fruit-zone along the east side (at complete veraison) (E); leaf removal in the fruit-zone along the east and west side (at complete veraison) (E/W); almost complete leaf removal along the west side (at complete veraison) and at pre-harvest also along the east side (F). For each defoliation thesis, half of the wine was treated with oak chips in order to verify whether the treatments with oak chips can mask the effects of defoliation. Defoliation partially affected the volatile profiles. Data concerning the volatile profiles show that the highest concentrations of total acids were detected in N and E wines, while those of the total ethyl esters were detected in F wines, and the lowest terpenes concentrations were found in E wines. The oak-treated wines show the highest contents of 1-heptanol, 1-octanol, many ethyl esters, and total hydrocarbons. They were the only in which the whisky lactone was detected. From a sensory point of view, the wines from almost completely defoliated grapes exhibited the lowest scores of gustatory-olfactory intensity, persistence, and quality. The wines that were not treated with chips exhibited sensory profiles characterized by floral and fruity notes, while those treated with oak chips showed sensory profiles characterized by spicy and fruity notes.

Effects of different vinification procedures and aging containers on phenolic and volatile composition of Greco white wines

Two wines, obtained respectively from Greco grapes submitted to (a) a traditional vinification in white and (b) a vinification including cryomaceration under reductive conditions, were aged for 12 months in glass container and in 3 types of amphorae (raw, glazed, and engobe). The wines obtained by cryomaceration under reductive conditions showed the highest phenolic contents both at racking and after aging. The phenolic contents decreased with aging and proanthocyanidins exhibited the greatest decrease. Antiradical/antioxidant activity at racking and after aging was higher in cryomacerated than in traditional wines. Antioxidant activity was not affected by the type of container. Volatile acids and esters decreased with aging, while alcohols, hydrocarbons, and aromatics increased. According to the principal component analysis (PCA) of results from conventional analyses and antioxidants, the wines were homogeneously grouped as a function of the vinification method applied. The PCA of volatile compounds allows to better emphasize the differences, grouping the data into three clusters according to the type of containers.

Mass spectrometry hyphenated techniques for the analysis of volatiles and peptides in soft cheese: Useful tools for the shelf life optimization.

In order to assess the product quality and shelf life of an Italian soft cream cheese under different storage conditions, the volatile and peptide profiles evolution were tested. Volatiles were sampled directly from the head space of cheese packaging by solid‐phase microextraction and analyzed by GC‐MS. Peptide profiles were obtained by nanoLC‐MS/MS, following a novel bioinformatics approach based on scoring distribution associated to the protein hits originating from the database search. In particular, a refined identification by focusing on selected time segments corresponding to the most intense peaks was carried out. A total of 40 compounds including acids, aldehydes, ketones, lactones, alcohols, esters, hydrocarbons, terpene, sulfur, and aromatic compounds were detected. Significant differences in their abundance during the storage in different packagings were observed, as well as an evolution of peptides mainly belonging to αS1‐casein. The results demonstrated the usefulness of the above‐mentioned hyphenated techniques for the determination of the soft cheese shelf life under different storage conditions.

Non-destructive testing of olive oil off-flavors by means of a micro-optic smart cap

The design and experimental setup of a smart cap are presented. It is capable of sniffing the vapors of extra virgin olive oil, thus alerting the consumer or the retailer of any rancid flavor. The cap is made of an array of metalloporphyrin-based optochemical sensors, the colors of which are modulated by the concentration of aldehydes, the main responsible for rancid off-flavors. A micro-optic device, implemented to simulate a cap prototype, is presented. The spectral response of the chromophore-array is processed by means of multivariate data analysis so as to achieve an artificial olfactory perception of oil aroma and, consequently, an indication of oil ageing and rancidity. In practice, the cap prototype proved to be a device for non-destructive testing of bottled oil quality.