Evaluation of the real nutritional value of processed food to improve their effect on health and increase their sustainability

Cured meats and dairy products are criticized for their salt content and synthetic additives. This has led to the development of strategies to reduce and replace these ingredients. Since the food matrix and technological processes can affect the bioaccessibility of nutrients, it is necessary to study their release during digestion to determine the real nutritional value of foods. In the first part of this PhD project, the impact on the nutritional quality of the reduction of sodium content and of the replacement of synthetic nitrates/nitrites with a combination of innovative formulations was evaluated in Parmigiano Reggiano Cheese and salami. For this purpose, an in vitro digestion model combined with different analytical techniques was used. The results showed that fatty acids and proteins release increased over time during digestion. At the end of digestion, the innovative formulation/processing did not negatively affect fatty acids release and protein hydrolysis, and led to the formation of bioactive peptides. The excessive intake of sugars is correlated with metabolic diseases. After the intestinal uptake, their release in the blood stream depends on their metabolic fate within the enterocyte. In the second part of this PhD project, the absorption and metabolism of glucose, fructose and sucrose was evaluated using intestinal cell line. A faster absorption of fructose than glucose was observed, and a different modulation of the synthesis/transport of other metabolites by monosaccharides was shown. Intestinal cells were also used to verify the stability and intestinal uptake of vitamins (A and D3) delivered to cells through two vehicles. It was shown that the presence of lipids protected the vitamin from external factors such as light, heat and oxygen, and improved their bioavailability Overall, the results obtained in this PhD project confirmed that considering only the chemical composition of foods is not sufficient to determine their nutritional value.

Effetto della temperatura di conservazione del latte, dalla raccolta all'affioramento, sulla microflora del latte, del sieroinnesto e del formaggio Trentingrana

This PhD research is part of a project addressed to improve the quality of Grana Trentino production. The objectives were to evaluated if milk storage and collection procedures may affect cheese-making technology and quality. Actually the milk is collected and delivered to the cheese factory just after milking in 50 L cans without refrigeration or in tanks cooled at 18 °C. This procedure is expensive (two deliveries each day) and the milk quality is difficult to preserve as temperatures are not controlled. The milk refrigeration at the farm could allow a single delivery to the dairy. Therefore it could be a good strategy to preserve raw milk quality and reduce cheese spoilage. This operation may, however, have the drawbacks of favouring the growth of psychrotrophic bacteria and changing the aptitude of milk to coagulation. With the aim of studying the effect on milk and cheese of traditional and new refrigerated technologies of milk storage, two different collection and creaming technologies were compared. The trials were replicated in three cheese factories manufacturing Grana Trentino. Every cheese-making day, about 1000 milk liters were collected from always the same two farms in the different collection procedures (single or double). Milk was processed to produce 2 wheels of Grana trentino every day. During the refrigerated trials, milk was collected and stored at the farm in a mixed tank at 12 or 8 °C and then was carried to the dairy in truck once a day. 112 cheese making day were followed: 56 for traditional technology and 56 for the refrigerated one. Each one of these two thechnologies lead to different ways of creaming: long time in the traditional one and shorter in the new one. For every cheese making day we recorded time, temperatures and pH during the milk processing to cheese. Whole milk before ceraming, cream and skim milk after creaming, vat milk and whey were sampled during every cheese-making day for analysis. After 18 months ripening we opened 46 cheese wheels for further chemical and microbiological analyses. The trials were performed with the aim of: 1 estimate the effect of storage temperatures on microbial communities, physico-chemical or/and rheological differences of milk and skim milk after creaming. 2 detect by culture dependent (plate counts) and indipendent (DGGE) methodolgies the microbial species present in whole, skimmed milk, cream and cheese sampled under the rind and in the core; 3 estimate the physico-chemical characteristics, the proteolytic activity, the content of free aminoacids and volatile compounds in 18 months ripened Grana Trentino cheeses from different storing and creaming of milk technologies. The results presented are remarkable since this is the first in-deep study presenting microbiological and chemical analysis of Grana Trentino that even if belonging to Grana Padano Consortium, it is clearly different in the milk and in the manufacturing technology.

Quali-quantitative study of the phenolic and polyphenolic compounds and their antioxidant capacity in vegetal matrix processed with different technologies

Food technologies today mean reducing agricultural food waste, improvement of food security, enhancement of food sensory properties, enlargement of food market and food economies. Food technologists must be high-skilled technicians with good scientific knowledge of food hygiene, food chemistry, industrial technologies and food engineering, sensory evaluation experience and analytical chemistry. Their role is to apply the modern vision of science in the field of human nutrition, rising up knowledge in food science. The present PhD project starts with the aim of studying and improving frozen fruits quality. Freezing process in very powerful in preserve initial raw material characteristics, but pre-treatment before the freezing process are necessary to improve quality, in particular to improve texture and enzymatic activity of frozen foods. Osmotic Dehydration (OD) and Vacuum Impregnation (VI), are useful techniques to modify fruits and vegetables composition and prepare them to freezing process. These techniques permit to introduce cryo-protective agent into the food matrices, without significant changes of the original structure, but cause a slight leaching of important intrinsic compounds. Phenolic and polyphenolic compounds for example in apples and nectarines treated with hypertonic solutions are slightly decreased, but the effect of concentration due to water removal driven out from the osmotic gradient, cause a final content of phenolic compounds similar to that of the raw material. In many experiment, a very important change in fruit composition regard the aroma profile. This occur in strawberries osmo-dehydrated under vacuum condition or under atmospheric pressure condition. The increment of some volatiles, probably due to fermentative metabolism induced by the osmotic stress of hypertonic treatment, induce a sensory profile modification of frozen fruits, that in some way result in a better acceptability of consumer, that prefer treated frozen fruits to untreated frozen fruits. Among different processes used, a very interesting result was obtained with the application of a osmotic pre-treatment driven out at refrigerated temperature for long time. The final quality of frozen strawberries was very high and a peculiar increment of phenolic profile was detected. This interesting phenomenon was probably due to induction of phenolic biological synthesis (for example as reaction to osmotic stress), or to hydrolysis of polymeric phenolic compounds. Aside this investigation in the cryo-stabilization and dehydrofreezing of fruits, deeper investigation in VI techniques were carried out, as studies of changes in vacuum impregnated prickly pear texture, and in use of VI and ultrasound (US) in aroma enrichment of fruit pieces. Moreover, to develop sensory evaluation tools and analytical chemistry determination (of volatiles and phenolic compounds), some researches were bring off and published in these fields. Specifically dealing with off-flavour development during storage of boiled potato, and capillary zonal electrophoresis (CZE) and high performance liquid chromatography (HPLC) determination of phenolic compounds.

Country-of-Origin Labeling for Processed Foods

The country-of-origin is the “nationality” of a food when it goes through customs in a foreign country, and is a “brand” when the food is for sale in a foreign market. My research on country-of-origin labeling (COOL) started from a case study on the extra virgin olive oil exported from Italy to China; the result shows that asymmetric and imperfect origin information may lead to market inefficiency, even market failure in emerging countries. Then, I used the Delphi method to conduct qualitative and systematic research on COOL; the panel of experts in food labeling and food policy was composed of 19 members in 13 countries; the most important consensus is that multiple countries of origin marking can provide accurate information about the origin of a food produced by two or more countries, avoiding misinformation for consumers. Moreover, I enhanced the research on COOL by analyzing the rules of origin and drafting a guideline for the standardization of origin marking. Finally, from the perspective of information economics I estimated the potential effect of the multiple countries of origin labeling on the business models of international trade, and analyzed the regulatory options for mandatory or voluntary COOL of main ingredients. This research provides valuable insights for the formulation of COOL policy.

Optimization of an innovative T6 heat treatment for the AlSi10Mg alloy processed by Laser-based Powder Bed Fusion: effect on microstructure, mechanical properties, and tribological behavior

Laser-based Powder Bed Fusion (L-PBF) technology is one of the most commonly used metal Additive Manufacturing (AM) techniques to produce highly customized and value-added parts. The AlSi10Mg alloy has received more attention in the L-PBF process due to its good printability, high strength/weight ratio, corrosion resistance, and relatively low cost. However, a deep understanding of the effect of heat treatments on this alloy's metastable microstructure is still required for developing tailored heat treatments for the L-PBF AlSi10Mg alloy to overcome the limits of the as-built condition. Several authors have already investigated the effects of conventional heat treatment on the microstructure and mechanical behavior of the L-PBF AlSi10Mg alloy but often overlooked the peculiarities of the starting supersatured and ultrafine microstructure induced by rapid solidification. For this reason, the effects of innovative T6 heat treatment (T6R) on the microstructure and mechanical behavior of the L-PBF AlSi10Mg alloy were assessed. The short solution soaking time (10 min) and the relatively low temperature (510 °C) reduced the typical porosity growth at high temperatures and led to a homogeneous distribution of fine globular Si particles in the Al matrix. In addition, it increased the amount of Mg and Si in the solid solution available for precipitation hardening during the aging step. The mechanical (at room temperature and 200 °C) and tribological properties of the T6R alloy were evaluated and compared with other solutions, especially with an optimized direct-aged alloy (T5 alloy). Results showed that the innovative T6R alloy exhibits the best mechanical trade-off between strength and ductility, the highest fatigue strength among the analyzed conditions, and interesting tribological behavior. Furthermore, the high-temperature mechanical performances of the heat-treated L-PBF AlSi10Mg alloy make it suitable for structural components operating in mild service conditions at 200 °C.