A critical evaluation on the valorization strategies to reduce and reuse orange waste in bakery industry.

Tons of orange by-products (OBPs) are generated during industrial orange processing. Currently, OBPs management is challenging due to their high amounts, physico-chemical characteristics (high water content, low pH, presence of essential oils) and seasonal nature of the production. Whereas agro-industrial OBPs can be highly valuable due to their abundant sources of bioactive compounds, which can add value to novel bakery products (e.g. bread, biscuits, cakes). This review covers the most recent research issues linked to the use of OBPs in bakery products, with a focus on available stabilization methods and on the main challenges to designing improved products. The application of OBPs improved the nutritional quality of bakery products, offering interesting sustainability benefits but also critical challenges. The valorization of OBPs may open new routes for the development of new natural ingredients for the food industry and lower food processing waste.

Effects of germination time on the structure, functionality, flavour attributes, and in vitro digestibility of green Altamura lentils (Lens culinaris Medik.) flour.

There has been an increase in the use of adoptable bioprocessing methods for the development of high-quality leguminous ingredients. The potential use of germinated green Altamura lentils as a food ingredient is closely related to the resulting properties. The objective of this study was to evaluate the impact of three germination times - 0 (C), 24 (G) and 48 (H) hours - on the physicochemical, microstructural, flavour, functional, and nutritional features of lentil flour samples (CF, GF and HF). Lentil flour samples were obtained by grinding both whole green seeds (C) and germinated seeds (G and H), and then sifting them to obtain a particle size < 300 µm. The germinated samples - GF (24 h) and HF (48 h) - exhibited differences (P < 0.05) in the physicochemical and bioactive properties of CF (control). Similarly, compared with those in the control sample, the total starch, amylose and total phenolic contents in the GF and HF samples decreased, while the protein content increased (p < 0.05). A decrease in the presence of intact starch granules was observed via SEM in the germinated samples. The germination time had a significant (P < 0.05) effect on the colour indices, L*, a*, and b* of the samples. Flavour attributes were significantly influenced by the germination time. Overall, a total of 14 (CF) and 17 (GF and HF) aromatic compounds were identified. The technological characteristics of the CF, GF and HF dough samples were studied using a Brabender farinograph. Germination time affects the flour properties, leading to a significant decrease in farinographic parameters such as water absorption (WA), dough development time (DT), and dough stability (DS) and an increase in the degree of dough weakening (DOS). Differential scanning calorimetry was employed to examine the gelatinization transition of the samples. Germination strongly influenced all the thermal properties of the samples. It also had a significant impact on the in vitro starch digestibility, starch fraction and glycaemic index (eGI) of the samples. In particular, the eGI of germinated lentils was lower than that of the CF. In conclusion, the germination time could be a key factor modulating some crucial lentil flour properties.

Compared digestibility of plant protein isolates by using the INFOGEST digestion protocol.

The use of ingredients based on plant protein isolates is being promoted due to sustainability and health reasons. However, it is necessary to explore the behaviour of plant protein isolates during gastrointestinal digestion including the profile of released free amino acids and the characterization of resistant domains to gastrointestinal digestion. The aim of the present study was to monitor protein degradation of four legume protein isolates: garden pea, grass pea, soybean and lentil, using the harmonized Infogest in vitro digestion protocol. In vitro digests were characterized regarding protein, peptide and free amino acid content. Soybean was the protein isolate with the highest percentage of insoluble nitrogen at the end of the digestion (12%), being this fraction rich in hydrophobic amino acids. Free amino acids were mainly released during the intestinal digestion, comprising 21-24% of the total nitrogen content, while the percentage of nitrogen corresponding to peptides ranged from 66 to 76%. Legume globulins were resistant to gastric digestion whereas they were hydrolysed into peptides and amino acids during the intestinal phase. However, the molecular weight (MW) distribution demonstrated that all intestinal digests, except those from soybean, contained peptides with MW > 4 kDa at the end of gastrointestinal digestion. The profile of free amino acids released during digestion supports legume protein isolates as an excellent source of essential amino acids to be used in protein-rich food products. Peptides released during digestion matched with previously reported epitopes from the same plant species or others, explaining the ability to induce allergic reactions and cross-linked reactivity.

Relationships between composition, microstructure and cooking performances of six potato varieties.

Potatoes tubers are the raw materials of many processed food, such as cooked potatoes in hot water, baked potatoes and the most popular fried potatoes. The objective of this work was to study the impact of boiling, baking and frying on microstructure and properties of six potato varieties (Agata, Agria, Innovator, Lady Rosetta, Musica and Spunta) with different origin. Scanning Electron Microscopy revealed significant differences between varieties and tuber microstructure changes following all cooking processes. Differential Scanning Calorimeter analysis showed that the transition temperatures (ranging between 60 °C and 85 °C) and enthalpies of gelatinization (2.1 J/g-3.9 J/g) of tubers were also variety dependent. In addition, the elasticity modulus of cooked samples depended on process type and followed the order: baked potatoes > boiled > fried potatoes. In particular, baked Lady Rosetta (224.3 kPa) showed the least decrease in rigidity between thermal processes. Fried Agria and Spunta, (56.3 and 61 kPa, respectively) had the smallest value of Young's modulus. Molecular marker analyses provided a genetic fingerprinting of our varieties, allowing the identification of diagnostic markers. Innovator revealed an important genetic distance from the other varieties. Such distance corresponded to its exclusive phenotypic traits, that are known to affect thermochemical properties. The information obtained in this work may be useful to further study and associate genetic sequences with appreciable food technological traits.

Visual evaluation of sliced Italian salami by image analysis.

Visual inspection is an important part of quality control not only for manufacturers but also for retailers and consumers. The object of this investigation was to determine fat content in sliced salami by means of image analysis. The image analysis procedure is applied to digital images of sliced Italian salami produced in 16 different salami factories (A-P). The image analysis method described in this work is nondestructive and the necessary equipment is cheap. It extracts directly interpretable parameters of fat particle morphology (e.g., area, roundness) and number of fat particles from 15 digital images for each sample (A-P). The correlations between the fat features extracted from the images with the chemical fat content measured on the samples were also studied. Good relationships were found between the fat particle characteristics measured by image analysis procedure and the percentage of chemically extractable fat by correlation (R2=0.75) and principal component analysis.

Current methods for mycotoxins analysis and innovative strategies for their reduction in cereals: an overview.

Mycotoxins are secondary metabolites produced by moulds in food that are considered a substantial issue in the context of food safety, due to their acute and chronic toxic effects on animals and humans. Therefore, new accurate methods for their identification and quantification are constantly developed in order to increase the performance of extraction, improve the accuracy of identification and reduce the limit of detection. At the same time, several industrial practices have shown the ability to reduce the level of mycotoxin contamination in food. In particular, a decrease in the amount of mycotoxins could result from standard processes naturally used for food processing or by procedures strategically introduced during processing, with the specific aim of reducing the amount of mycotoxins. In this review, the current methods adopted for accurate analyses of mycotoxins in cereals (aflatoxins, ochratoxins, trichothecenes, fumonisins) are discussed. In addition, both conventional and innovative strategies adopted to obtain safer finished products from common cereals intended for human consumption will be explored and analysed. © 2018 Society of Chemical Industry.

Microstructure and tuber properties of potato varieties with different genetic profiles.

The objectives of this research were to study tuber starch characteristics and chemical - thermal properties of 21 potato varieties, and to determine their genetic diversity through SSR markers. Starch granular size varied among samples, with a wide diameter distribution (5-85µm), while granule shapes were similar. Differential Scanning Calorimeter analysis showed that the transition temperatures (69°C-74°C) and enthalpies of gelatinization (0.9J/g-3.8J/g) of tubers were also variety dependent. SSR analysis allowed the detection of 157 alleles across all varieties, with an average value of 6.8 alleles per locus. Variety-specific alleles were also identified. SSR-based cluster analysis revealed that varieties with interesting quality attributes were distributed among all clusters and sub-clusters, suggesting that the genetic basis of traits analyzed may differ among our varieties. The information obtained in this study may be useful to identify and develop varieties with slowly digestible starch.

Characterisation, in vitro digestibility and expected glycemic index of commercial starches as uncooked ingredients.

In this study native starches as ingredients (corn, rice, wheat, tapioca and potato) were characterized for microstructure, physicochemical, functional and thermal properties, in vitro digestibility and glycemic index. There was a significant variation in the granule shape and size distribution of the starches. Particle size monomodal (corn, tapioca, potato) and bimodal (rice, wheat) distribution was observed amongst the starches. The potato starch showed the biggest size granules while the rice showed the smallest. The examined properties and nutritional characteristics of starches were significantly different. Thermal properties were studied using Differential Scanning Calorimeter (DSC). DSC results showed that the transition temperatures (58.8-78.7 °C) and enthalpies of gelatinization (2.3-8.2 J/g) of the starches appeared to be greatly influenced by microstructure and chemical composition (e.g. resistant starch). Nutritional properties such as slowly digestible starch and expected glycemic index values followed the order: rice > wheat > tapioca > corn > potato. In particular, the highest resistant starch was recorded for potato starch.

Optimization of water curing for the preservation of chestnuts (Castanea sativa Mill.) and evaluation of microbial dynamics during process.

Chestnuts are very perishable fruits, whose quality may be compromised during postharvest handling. Damage can be caused both by insects and fungi. Water curing, a commonly used postharvest method, is based on soaking fruits in water typically for about one week. Factors that affect effectiveness of water curing have only been explained partially. A decrease in pH, likely imputable to a light fermentation caused by lactic acid bacteria, may inhibit the growth of moulds. In this study a Lactobacillus pentosus strain was selected for its ability to inhibit fungi, and used as a starter culture during water curing. As second goal, a reduction of the environmental impact of the process was evaluated by using water that had been re-cycled from a previous curing treatment. Experiments were performed on pilot as well as on farm scale. In all trials, microbial dynamics were evaluated by means of a polyphasic approach including conventional and molecular-based analyses. According to results, the employment of an adjunct culture appears as a very promising opportunity. Even if no reduction in the duration of the process was achieved, waters exhibited a minor microbial complexity and fruits did not lose the natural lustre after the process.

The relevance of the collaborative effect in determining the performances of photorefractive polymer materials.

A derivative of 2-methylindole, 3-[2-(4-nitrophenyl)ethenyl]-1-allyl-2-methylindole, NPEMI-A, is studied for its photoconductivity and photorefractivity behaviour. Its blends with the organic polymer poly-(2,3-dimethyl-N-vinylindole), PVDMI, are also investigated. Due to the expected and devised mutual solubility of the two components of the blends, it is possible to carry out measurements with the weight percent of the chromophore NPEMI-A changing from zero to 100. Films were produced by a squeezing process between two ITO-covered glass sheets. No opacity phenomena, that are so common for many other organic blends due to the segregation of the dissolved chromophore, are observed. The photorefractive optical gain Gamma(2) is obtained as a function of the chromophore content. Differential scanning calorimetry measurements (DSC) are also carried out to obtain the whole change of the glass transition temperature T(g) as a function of the amount of chromophore contained in the blends. From the experimental trend of T(g) a meaningful quantitative estimate of the value of the electrostatic interactions acting in the studied blends, is obtained. The importance of the value of T(g), and of the electrostatic interactions, in determining the extent of the photorefractivity is clearly evident. The results are compared for NPEMI-A (Gamma(2) = 210 cm(-1)) and for NPEMI-E (Gamma(2) approximately = 2000 cm(-1)) that has a N-2-ethylhexyl group instead of a N-allyl group. The Pockels and Kerr contributions and--for the first time--a "collaborative effect" of the photorefractivity of NPEMI-A are distinguished and quantitatively evaluated.

Unconditionally stable indole-derived glass blends having very high photorefractive gain: the role of intermolecular interactions.

The photorefractivity of an indole derivative and of its polymer blends has been studied at room temperature. The indole derivative 3-[2-(4-nitrophenyl)ethenyl]-1-(2-ethylhexyl)-2-methylindole (NPEMI-E) is a typical low-molecular-weight glass-forming molecule having peculiar nonlinear optics characteristics. It is unconditionally soluble in the photoconductive poly-(N-vinyl-2,3-dimethylindole) so that all the possible blends can be studied for a weight percent (wt. %) content of NPEMI-E ranging from zero to 100. A very high and sharp maximum of the photorefractive optical gain Gamma(2) approximately 2000 cm(-1) was obtained for a NPEMI-E wt. % content of about 90. On the basis of recently published theoretical calculations, we have made the hypothesis that the rapid change of Gamma(2) can also be ascribed to a correspondingly quick variation of the molecular electro-optic parameters of the dissolved chromophore for some well distinguished values of its concentration in the polymer matrix. Differential scanning calorimetry measurements were made and the results carefully analyzed with the aim of obtaining information on the intermolecular interactions. These last measurements also allowed rationalizing the unconditionally stable glass appearance of the obtained blends. Measurements of spectroscopic ellipsometry were also made on blends with different NPEMI-E content.

Photorefractivity of poly-N-vinylindole-based materials as compared with that of poly-N-vinylcarbazole-based blends.

The asymmetric two-beam coupling technique has been employed to measure the photorefractivity of thin films of polymer blends containing 2,5-dimethyl-4-(p-nitrophenylazo)anisole as the nonlinear optical component. Poly-(1-vinylindole) and poly-(2,3-dimethyl-1-vinylindole) were the photoconductive polymer counterparts. The values of the photorefractivity are reported. It appears that they are comparable with those of similar blends based on the well-known poly-(9-vinylcarbazole) (PVK), here considered as a reference standard. Careful differential scanning calorimetry analyses have been accomplished on the different blends taken into account to rationalize the significantly longer shelf lifetime of the indolyl-based films with respect to the PVK-based blends.