Costantino Fadda

Bread Staling: Updating the View

Staling of bread is cause of significant product waste in the world. We reviewed the literature of the last 10 y with the aim to give an up-to-date overview on processing/storage parameters, antistaling ingredients, sourdough technology, and measurement methods of the staling phenomenon. Many researchers have been focusing their interest on the selection of ingredients able to retard staling, mainly hydrocolloids, waxy wheat flours (WWF), and enzymes, but different efforts have been made to understand the molecular basis of bread staling with the help of various measurement methods. Results obtained confirm the central role of amylopectin retrogradation and water redistribution within the different polymers in determining bread staling, but highlighted also the importance of other flour constituents, such as proteins and nonstarch polysaccharides. Data obtained with thermal, spectroscopy, nuclear magnetic resonance, X-ray crystallography, and colorimetry analysis have pointed out the need to encourage the use of one or more of these techniques in order to better understand the mechanisms of staling. Results so far obtained have provided new insight on bread staling, but the phenomenon has not been fully elucidated so far.

Impact of ancient cereals, pseudocereals and legumes on starch hydrolysis and antiradical activity of technologically viable blended breads

Wheat flour replacement from 22.5% up to 45% by incorporation of ternary blends of teff (T), green pea (GP) and buckwheat (BW) flours provided technologically viable and acceptable sensory rated multigrain breads with superior nutritional value compared to the 100% wheat flour (WT) counterparts. Blended breads exhibited superior nutritional composition, larger amounts of bioaccessible polyphenols, higher anti-radical activity, and lower and slower starch digestibility. Simultaneous lower rapidly digestible starch (57.1%) and higher slowly digestible starch (12.9%) and resistant starch (2.8%) contents (g per 100g fresh bread), considered suitable nutritional trends for dietary starch fractions, were met by the blend formulated 7.5% T, 15% GP, 15% BK. The associated mixture that replaced 37.5% WT, showed a rather lower extent and slower rate of starch hydrolysis with medium-low values for C∞, and H90, and lowest k, and intermediate expected Glycaemic Index (86). All multigrain breads can be labelled as source of dietary fibre (≥ 3 g dietary fibre/100g bread).

Changes during storage of quality parameters and in vitro antioxidant activity of extra virgin monovarietal oils obtained with two extraction technologies

Extraction technology has a great effect on quality of olive oils. This paper studied 18 months of storage of two Sardinian extra virgin monovarietal oils obtained with a traditional and with a low oxidative stress technology. Oil samples were subjected to the following chemical analyses: acidity, peroxide value, ultraviolet light absorption K₂₃₂ and K₂₇₀, carotenoids, chlorophylls, tocopherols and total polyphenols. The antioxidant capacity of oils, polyphenol extract and oil extract (remaining after polyphenol extraction) was also determined as radical scavenging activity. The results show that both extraction technologies resulted in minor changes in legal and quality indices during storage, due surely to the high quality of the oils as well as to the very good storage conditions used. Oils obtained with the low oxidative stress technology showed lower peroxide value and acidity and resulted in up to 103% higher total polyphenol content as well as increased radical-scavenging activity, with respect to oils obtained with the traditional technology.

Gluten-free dough-making of specialty breads: Significance of blended starches, flours and additives on dough behaviour

The capability of different gluten-free (GF) basic formulations made of flour (rice, amaranth and chickpea) and starch (corn and cassava) blends, to make machinable and viscoelastic GF-doughs in absence/presence of single hydrocolloids (guar gum, locust bean and psyllium fibre), proteins (milk and egg white) and surfactants (neutral, anionic and vegetable oil) have been investigated. Macroscopic (high deformation) and macromolecular (small deformation) mechanical, viscometric (gelatinization, pasting, gelling) and thermal (gelatinization, melting, retrogradation) approaches were performed on the different matrices in order to (a) identify similarities and differences in GF-doughs in terms of a small number of rheological and thermal analytical parameters according to the formulations and (b) to assess single and interactive effects of basic ingredients and additives on GF-dough performance to achieve GF-flat breads. Larger values for the static and dynamic mechanical characteristics and higher viscometric profiles during both cooking and cooling corresponded to doughs formulated with guar gum and Psyllium fibre added to rice flour/starch and rice flour/corn starch/chickpea flour, while surfactant- and protein-formulated GF-doughs added to rice flour/starch/amaranth flour based GF-doughs exhibited intermediate and lower values for the mechanical parameters and poorer viscometric profiles. In addition, additive-free formulations exhibited higher values for the temperature of both gelatinization and retrogradation and lower enthalpies for the thermal transitions. Single addition of 10% of either chickpea flour or amaranth flour to rice flour/starch blends provided a large GF-dough hardening effect in presence of corn starch and an intermediate effect in presence of cassava starch (chickpea), and an intermediate reinforcement of GF-dough regardless the source of starch (amaranth). At macromolecular level, both chickpea and amaranth flours, singly added, determined higher values of the storage modulus, being strengthening effects more pronounced in presence of corn starch and cassava starch, respectively.

Techno-functional and nutritional performance of commercial breads available in Europe

In recent years, the growing interest for well-being and healthy lifestyle together with an increasing awareness of the close relationship between food and health have boosted the production of an increasing number of novel goods to be placed in both gluten-containing and gluten-free products market. The objective of this study was to provide a realistic and detailed overview of the current bread-market supply in order to evaluate the overall quality of the available offer in this prioritized food industry area. Twenty commercial breads consisting of gluten (n = 10) and gluten-free (n = 10) samples currently available in the European market have been assessed by physical-chemical, technological, nutritional, and sensory determinations. The quality parameters obtained were related to each other by using Pearson correlations, while sample classification was achieved by applying factor analysis. Higher values for protein and bio-accessible polyphenols content, aroma and taste quality, and low and moderate expected glycaemic index corresponded to gluten containing breads. Although the main distinction was between gluten and gluten-free samples as it was expected, classification of breads allowed differentiating samples with different formulations in terms of presence/absence of alternative, innovative, and nutrient-dense raw materials.

Effect of ripening stage at harvest, cold storage, and simulated marketing conditions on quality and antioxidant activity of peach fruit

The influence of storage time on different quality parameters and in vitro antioxidant activity of peaches cv. Elegant Lady harvested at two ripening stages (immature and commercial mature) and stored under cold and marketing conditions were assessed. Destructive (physical-chemical properties, antioxidant activity, and firmness) and nondestructive parameters (colour and index of absorbance difference, IAD) were assessed. Storage and ripening stage influenced firmness, colour, and antioxidant activity. Firmness decreased significantly during cold and marketing storage, and skin colour parameters, a* and b*, underwent a deepening of the red hue, while IAD values fully justified differences in colour over storage time and ripening stage. The antioxidant activity increased during storage, although polyphenols and ascorbic acid contents remained constant, and was higher in commercial mature fruit than immature peaches, that revealed a ratio of total sugars/total acids more equilibrated.

Intra-varietal Agronomical Variability in Vitis vinifera L. cv. cannonau investigated by fluorescence, texture and colorimetric analysis

To date, innovative, rapid and non-invasive techniques have been used to assess variations in morphological and technological characteristics between grape cultivars. In order to improve knowledge of the qualitative expression of the genetic traits of cv. Cannonau (syn. Grenache), fluorescence, texture and colorimetric analyses were performed on 85 biotypes attributable to this variety. Eighty-five Cannonau biotypes cultivated in the same vineyard were analysed in order to evaluate their morphological and agronomical characteristics. As regards the morphological traits, of the six descriptors observed, five were able to discriminate the Cannonau population according to different expression levels. Must composition, berry colour (using the Minolta tristimulus colorimeter), texture (assessed using the TaxT2i plus texturimeter) and fluorescence (using the Multiplex III detector) were determined on clusters harvested at the same time. Cluster analysis was able to separate the Cannonau population into five groups, characterised by differences in the following criteria: L*, a* and b*, berry skin thickness, FERARI, TSS, pH and titratable acidity, total polyphenols and total anthocyanins. The FERARI index was highly and positively correlated with total anthocyanins and negatively correlated with grape colour, while berry weight and berry skin thickness were not correlated with any variable assessed. The remarkable intra-variability encountered for the qualitative and quantitative characters in the Cannonau variety suggests that new biotypes could be selected for different oenological purposes, using techniques such as the measure of fluorescence and colorimetry. This is the first study carried out within the cv. Cannonau using innovative and classical techniques suitable to investigate intra-varietal variability.

Antioxidant activity and sensory changes of strawberry tree fruits during cold storage and shelf life

Fadda C., Fenu P.A.M., Usai G., Del Caro A., Diez Y.M., Sanguinetti A.M., Piga A. (2015): Antioxidant activity and sensory changes of strawberry tree fruits during cold storage and shelf life. Czech J. Food Sci., 33: 531–536. The influence of storage time on a range of quality parameters, in vitro antioxidant activity, and the sensory acceptability of fully ripe strawberry tree fruits packaged into polypropylene trays under plastic film was assessed. Fruits were stored at 0°C for 6, 12 or 18 days and then transferred to shelf life at 20°C for 2 days. The parameters most influenced by cold storage and shelf life were firmness, colour, and antioxidant activity. Firmness decreased significantly during storage and colour parameters showed a decrease in saturation. Significant increases in polyphenols and anthocyanins were registered during storage, with a resulting increase in total antioxidant activity. The sensory analysis demonstrated that fruits maintain an acceptable quality level for up to 1 day under shelf life conditions following 18 days of cold storage.

The Effects of Ovine Whey Powders on Durum Wheat-Based Doughs

Two types of ovine whey powder, with different protein content, were added at increasing substitution rates to two types of semolina, one with strong and tenacious gluten and the other with weak and sticky gluten. For each dough the optimum mixing time and hydration level were calculated using the consistograph. The whey powder negatively affected the leavening volume of all doughs, at all percentages except the lowest one (5%), mainly because of its effects on the elastic component of gluten as measured with a stress relaxation test. Differences of the secondary structure of gluten proteins among samples were investigated by analyzing the amide I band in the Fourier transform infrared spectra of the dough. Weak and strong semolina showed a different relative percentage of α-helix, random coil, and β-sheet structures. The longer mixing times for dough formation when using semolina with strong gluten led to an increase in α-helices and random coils, which caused a worse leavening performance than the weak-gluten semolina.

Improving Baking Quality of Weak Gluten Semolina Using Ovine Whey Powder

The effect of the addition of ovine whey powder at 5%, 10%, and 15% on bread quality was studied. Two different types of semolina were used, one being a commercial blend with strong and tenacious gluten (48T) and the other coming from one single cultivar, characterized for having weak and sticky gluten (4T). Two different types of typical Mediterranean bread were produced, pan bread and flat bread, and their quality characteristics were measured, together with their shelf life. The volume of 4T pan bread was improved by the addition of 5% ovine whey powder. In the case of 48T, the volume of bread was negatively affected by the addition of ovine whey powder. Moreover, flat bread made with 4T was more extensible after the addition of ovine whey powder and showed lower starch retrogradation over time than the same type of bread made with 48T. Among the different pan bread types, consumers preferred 4T with 5% of substitution, which also showed an improved cell size distribution in the crumb.