Ivano De Noni

Cooking Properties and Heat Damage of Dried Pasta as Influenced by Raw Material Characteristics and Processing Conditions

Dried pasta represents a primary food in the diet of many populations who mainly perceive its quality in terms of cooking performances. Indeed, this and other aspects of pasta quality arise from several technological parameters starting from the usage of durum wheat semolina as raw material. In this paper, the chemical and physical characteristics of semolina directly related to dried pasta quality are discussed, taking into account the biochemical phenomena involving semolina components and occurring during the whole pasta-making chain. The quality of pasta is also discussed with relation to drying conditions which account for both the ultrastructural changes in protein and starch organization and the occurrence of unnatural molecules arising from the Maillard reaction. The information provided here suggests that a comprehensive evaluation of pasta quality should include heat-damage induced by processing conditions.

Bacterial Cinnamoyl Esterase Activity Screening for the Production of a Novel Functional Food Product

ABSTRACT Lactobacillus helveticus MIMLh5 was selected for its strong cinnamoyl esterase activity on chlorogenic acid and employed for the preparation of a food product containing a high concentration of free caffeic acid. The novel food product was demonstrated to display high total antioxidant power and potential probiotic properties.

Modulation of Fecal Clostridiales Bacteria and Butyrate by Probiotic Intervention with Lactobacillus paracasei DG Varies among Healthy Adults

BACKGROUND The modulation of gut microbiota is considered to be the first target to establish probiotic efficacy in a healthy population. OBJECTIVE This study was conducted to determine the impact of a probiotic on the intestinal microbial ecology of healthy volunteers. METHODS High-throughput 16S ribosomal RNA gene sequencing was used to characterize the fecal microbiota in healthy adults (23-55 y old) of both sexes, before and after 4 wk of daily consumption of a capsule containing at least 24 billion viable Lactobacillus paracasei DG cells, according to a randomized, double-blind, crossover placebo-controlled design. RESULTS Probiotic intake induced an increase in Proteobacteria (P = 0.006) and in the Clostridiales genus Coprococcus (P = 0.009), whereas the Clostridiales genus Blautia (P = 0.036) was decreased; a trend of reduction was also observed for Anaerostipes (P = 0.05) and Clostridium (P = 0.06). We also found that the probiotic effect depended on the initial butyrate concentration. In fact, participants with butyrate >100 mmol/kg of wet feces had a mean butyrate reduction of 49 ± 21% and a concomitant decrease in the sum of 6 Clostridiales genera, namely Faecalibacterium, Blautia, Anaerostipes, Pseudobutyrivibrio, Clostridium, and Butyrivibrio (P = 0.021), after the probiotic intervention. In contrast, in participants with initial butyrate concentrations <25 mmol/kg of wet feces, the probiotic contributed to a 329 ± 255% (mean ± SD) increment in butyrate concomitantly with an ∼55% decrease in Ruminococcus (P = 0.016) and a 150% increase in an abundantly represented unclassified Bacteroidales genus (P = 0.05). CONCLUSIONS The intake of L. paracasei DG increased the Blautia:Coprococcus ratio, which, according to the literature, can potentially confer a health benefit on the host. The probiotic impact on the microbiota and on short-chain fatty acids, however, seems to strictly depend on the initial characteristics of the intestinal microbial ecosystem. In particular, fecal butyrate concentrations could represent an important biomarker for identifying subjects who may benefit from probiotic treatment. This trial was registered at www.controlled-trials.com/isrctn as ISRCTN56945491.

Release of β-casomorphins 5 and 7 during simulated gastro-intestinal digestion of bovine β-casein variants and milk-based infant formulas

The release of β-casomorphin-5 (BCM5) and β-casomorphin-7 (BCM7) was investigated during simulated gastro-intestinal digestion (SGID) of bovine β-casein variants (n=3), commercial milk-based infant formulas (n=6) and experimental infant formulas (n=3). SGID included pepsin digestion at pH 2.0, 3.0 and 4.0 and further hydrolysis with Corolase PP™. β-Casein (β-CN) variants were extracted from raw milks coming from cows of Holstein-Friesian and Jersey breeds. Genomic DNA was isolated from milk and the β-CN genotype was determined by a PCR-based method. Phenotype at protein level was determined by capillary zone electrophoresis in order to ascertain the level of gene expression. Recognition and quantification of BCMs involved HPLC coupled to tandem MS. Regardless of the pH, BCM7 generated from variants A1 and B of β-CN (5-176mmol/mol casein) the highest amount being released during SGID of form B. As expected, the peptide was not released from variant A2 at any steps of SGID. BCM5 was not formed in hydrolysates irrespective of either the genetic variant or the pH value during SGID. Variants A1, A2 and B of β-CN were present in all the commercial infant formulae (IFs) submitted to SGID. Accordingly, 16-297nmol BCM7 were released from 800ml IF, i.e. the daily recommended intake for infant. Industrial indirect-UHT treatments (156°C×6-9s) did not modify release of BCM7 and, during SGID, comparable peptide amounts formed in raw formulation and final heat-treated IFs.

S-layer protein mediates the stimulatory effect of Lactobacillus helveticus MIMLh5 on innate immunity.

ABSTRACT The ability to positively affect host health through the modulation of the immune response is a feature of increasing importance in measuring the probiotic potential of a bacterial strain. However, the identities of the bacterial cell components involved in cross talk with immune cells remain elusive. In this study, we characterized the dairy strain Lactobacillus helveticus MIMLh5 and its surface-layer protein (SlpA) using in vitro and ex vivo analyses. We found that MIMLh5 and SlpA exert anti-inflammatory effects by reducing the activation of NF-κB on the intestinal epithelial Caco-2 cell line. On the contrary, MIMLh5 and SlpA act as stimulators of the innate immune system by triggering the expression of proinflammatory factors tumor necrosis factor alpha and COX-2 in the human macrophage cell line U937 via recognition through Toll-like receptor 2. In the same experiments, SlpA protein did not affect the expression of the anti-inflammatory cytokine interleukin-10. A similar response was observed following stimulation of macrophages isolated from mouse bone marrow or the peritoneal cavity. These results suggest that SlpA plays a major role in mediating bacterial immune-stimulating activity, which could help to induce the hosts defenses against and responses toward infections. This study supports the concept that the viability of bacterial cells is not always essential to exert immunomodulatory effects, thus permitting the development of safer therapies for the treatment of specific diseases according to a paraprobiotic intervention.

Spaghetti from durum wheat: Effect of drying conditions on heat damage, ultrastructure and in vitro digestibility

The effects of low (LT) or high (HT) temperature drying on ultrastructural, molecular and in vitro digestibility properties of cooked spaghetti were studied. Starch swelling and denaturation/aggregation of proteins occurring at diverse stages, LT or HT drying and cooking, resulted in different in vitro digestibility of spaghetti. For the first time, these differences were assessed in terms of the release of free AA and simple sugars. Indeed, at the end of in vitro digestion, the total amount of released maltotriose, maltose and glucose significantly differentiated digestates of LT and HT spaghetti (12.6 and 15.9 g 100g⁻¹). In the same samples, diverse amounts (16.3 and 12.5 g 100g⁻¹ protein) of free amino acids were found. Chemical artifacts occurring at protein level impaired release of lysine in cooked HT spaghetti after in vitro digestion. These results increase the knowledge on digestibility of LT and HT cooked spaghetti.

Aspartate Biosynthesis Is Essential for the Growth of Streptococcus thermophilus in Milk, and Aspartate Availability Modulates the Level of Urease Activity

ABSTRACT We investigated the carbon dioxide metabolism of Streptococcus thermophilus, evaluating the phenotype of a phosphoenolpyruvate carboxylase-negative mutant obtained by replacement of a functional ppc gene with a deleted and inactive version, Δppc. The growth of the mutant was compared to that of the parent strain in a chemically defined medium and in milk, supplemented or not with l-aspartic acid, the final product of the metabolic pathway governed by phosphoenolpyruvate carboxylase. It was concluded that aspartate present in milk is not sufficient for the growth of S. thermophilus. As a consequence, phosphoenolpyruvate carboxylase activity was considered fundamental for the biosynthesis of l-aspartic acid in S. thermophilus metabolism. This enzymatic activity is therefore essential for growth of S. thermophilus in milk even if S. thermophilus was cultured in association with proteinase-positive Lactobacillus delbrueckii subsp. bulgaricus. It was furthermore observed that the supplementation of milk with aspartate significantly affected the level of urease activity. Further experiments, carried out with a pureI-gusA recombinant strain, revealed that expression of the urease operon was sensitive to the aspartate concentration in milk and to the cell availability of glutamate, glutamine, and ammonium ions.

Occurrence and fate of ACE-inhibitor peptides in cheeses and in their digestates following in vitro static gastrointestinal digestion

The occurrence of the casein-derived angiotensin converting enzyme-inhibitor (ACE-I) peptides VPP, IPP, RYLGY, RYLG, AYFYPEL, AYFYPE, LHLPLP and HLPLP were investigated in 12 different cheese samples by Ultra Performance Liquid Chromatography/High-Resolution Mass Spectrometry. The total amount of ACE-I peptides was in the range 0.87-331mgkg(-1). VPP and IPP largely prevailed in almost all cheeses. Following in vitro static gastrointestinal digestion of Cheddar, Gorgonzola, Maasdam and Grana Padano cheeses, type and amount of ACE-I peptides changed, and only VPP, IPP, HLPLP and LHLPLP were detected in the intestinal digestates. The results evidenced that the degree of proteolysis itself cannot be regarded as a promoting or hindering factor for ACE-I peptide release during cheese digestion. Moreover, the data indicated that the ACE-I potential of cheeses cannot be inferred based on the type and amount of ACE-I peptides present in undigested samples.

Determination of Reduced Cysteine in Oenological Cell Wall Fractions of Saccharomyces cerevisiae

Compounds containing cysteine residues, such as glutathione, can affect the redox potential of must and wine by reduction of o-quinones and hydrogen peroxide. The oenological yeast cell wall fractions contain cysteine residues in their protein structure, and they could affect both oxidative and odor properties of wine. An analytical approach based on the derivatization of cysteinyl residues with p-benzoquinone followed by reversed-phase high-performance liquid chromatography separation was developed to quantify glutathione and free and protein cysteine in 16 Saccharomyces cerevisiae strains and 12 commercial samples of yeast mannoproteins, hulls, and lysates. The chemical modifications induced by the Maillard reaction following the industrial preparation of such fractions were evaluated as well. Lysates showed the highest protein cysteine content and high contents of glutathione and free cysteine. Mannoproteins showed an intense Maillard reaction (furosine >60 mg/100 g protein), and most of the samples were able to bind thiol compounds with a potentially detrimental effect toward the thiol-related odors in wine.

‘Melatonin isomer’ in wine is not an isomer of the melatonin but tryptophan-ethylester

Melatonin is a neurohormone, chronobiotic, and antioxidant compound found in wine and deriving directly from grapes and/or synthesized by yeast during alcoholic fermentation. In addition, a melatonin isomer has been detected in different foods, wine among them. The special interest for melatonin isomer related to the fact that it was found in greater quantities than melatonin and probably shares some of its biological properties. Despite this, its chemical structure has not yet been defined; although some researchers hypothesize, it could be melatonin with the ethylacetamide group shifted into position N1. Thus, the aim of our study was to identify the structures of the melatonin isomer. For this purpose, melatonin and melatonin isomer in Syrah wine were separated chromatographically by a sub‐2 μm particle column and detected by tandem mass spectrometry. The sample was then purified and concentrated by solid‐phase extraction, hydrolyzed with alkali or esterase, and substrates and products quantified by UPLC‐MS/MS. Moreover, melatonin, melatonin isomer, and their product ions were evaluated by high‐resolution mass spectrometry. The amount of melatonin isomer and melatonin in the wine was 84 ± 4 and 3 ± 0 ng/mL, respectively. In the solutions, containing diluted alkali or esterase, melatonin isomer was hydrolyzed in about 8 min. Correspondingly, tryptophan was detected, and its amount increased and reached the maximum concentration in about 8 min. Melatonin concentration was not affected by diluted alkali or esterase. The fragmentation pattern of melatonin isomer was different from that of melatonin but comparable to that of tryptophan‐ethylester. Finally, the so‐called melatonin isomer identity was verified by cochromatography with authentic standard of tryptophan‐ethylester.