Phenolic lipids as unique bioactive compounds: a comprehensive review on their multifunctional activity toward the prevention of Alzheimer's disease.

Phenolic lipids are multifunctional compounds which play an important biological role in the body. Their unique biologic functionality stems from their strong amphiphilic character which allows them to be incorporated in erythrocytes. Through membrane incorporation, these compounds exert their biological effects on neurons which are not modulated by hydrophilic compounds. These bioactive compounds are present in nature as secondary plant metabolites, and consequently their availability is limited, for dietary and medical purposes. In this review, the pathways and mechanisms associated with the pathogenesis of Alzheimer's disease will be described. In addition, the modulatory effects of phenolic lipids on these pathways and a list of several synthetic, semi synthetic and natural sources of phenolic lipids will be examined as having the potential to prevent or combat Alzheimer's disease.

Physicochemical, antioxidant, calcium binding, and angiotensin converting enzyme inhibitory properties of hydrolyzed tomato seed proteins.

The objective of this was to determine the impact of enzymatic hydrolysis on the multifunctionality of tomato seed protein hydrolysates (TSPH) and their physicochemical properties. The enzymatic hydrolysis was performed using alcalase and two factors response surface methodology. The best conditions were 131.4 min and 3% enzyme/substrate (E/S) for antioxidant activity; 174.5 min and 2.93% E/S for angiotensin-converting enzyme (ACE) inhibition; and 66.79 min and 2.27% E/S for the calcium binding. Antioxidant and ACE hydrolysates were characterized by higher solubility, zeta potential, and thermal stability while properties of the calcium binding hydrolysate were only minimally affected by the enzymatic hydrolysis. Gel electrophoresis showed that molecular weights of polypeptides in the calcium binding TSPH were higher compared to those in ACE and antioxidant TSPHs. This was due to the low degree of hydrolysis of the calcium binding hydrolysate. PRACTICAL APPLICATIONS: Nowadays, different protein sources are used to produce protein hydrolysates containing bioactive peptides that can help alleviate oxidation of foods, oxidative stress, and chronic conditions (e.g., hypertension, diabetes, cardiovascular disorder). Hydrolyzed proteins also have the potential to increase mineral absorption through the formation of mineral-binding complexes. Biological activities of proteins and peptides from tomato processing byproduct (i.e., pomace) have received until now little attention. The determination of physicochemical properties and biological activities of the hydrolyzed proteins has application in the formulation of value-added food products for the reduction of oxidative stress and risks of developing chronic diseases. In addition, there will be a reduction of pomace waste generated by the tomato processing industry.

Production of antioxidant peptide fractions from a by-product of tomato processing: mass spectrometry identification of peptides and stability to gastrointestinal digestion.

In this study, proteins were extracted from tomato seeds, the main by-product of tomato processing. The incubation for 138.62 min coupled with 3% alcalase was observed to be optimum to produce a tomato seed protein hydrolysate (TSPH) with the highest antioxidant properties. Under these conditions, predicted TSPH activities were 62.99% scavenging of DPPH radicals and 54.81% reduction of phosphomolybdate. Separation of TSPH by ultrafiltration provided three fractions (UF1-UF3) of which, UF3 (< 3 kDa) showed the strongest activity (73.15% DPPH scavenging and 60.1% phosphomolybdate reduction). UF3 was further separated by RP-HPLC into sub-fractions F1-F6. Biological testing found that F2 and F4 were the most active in scavenging DPPH radicals (60.36 and 21.23%) and reducing phosphomolybdate (57.3 and 48.0%). LC-ESI-MS/MS analysis showed that the higher activity of F2 might be explained by the presence of more peptides that contained tyrosine and histidine, known to enhance antioxidant activity through hydrogen or electron transfer. In the simulated gastrointestinal digestion test, peptides in F2 were more resistant compared to those in F4. These findings indicate that peptide fraction F2 might be more useful in the formulation of functional foods because of its greater antioxidant activity and resistance to digestion.

Study of antioxidant activity of sheep visceral protein hydrolysate: Optimization using response surface methodology.

BACKGROUND: The main objective of this experiment was optimal use of none edible protein source to increase nutritional value of production with high biological function, including antioxidant activity. METHODS: Sheep visceral (stomach and intestine) was used as substrate. Response surface methodology (RSM) was used to optimize hydrolysis conditions for preparing protein hydrolysate from the sheep visceral, using alcalase 2.4 l enzyme. The investigated factors were temperature (43-52 °C), time (90-180 min), and enzyme/substrate ratio [60-90 Anson-unit (AU)/kg protein] to achieve maximum antioxidant activity. Experiments were designed according to the central composite design. RESULTS: Each of the studied variables had a significant effect on responses (P < 0.05). Optimal conditions to achieve antioxidant activity were, temperature (48.27 °C), time (158.78), min and enzyme/substrate ratio (83.35) Anson-unit/kg protein. Under these conditions, antioxidant activity was 68.21%, R2 for model was 0.983. The values indicated the high accuracy of the model to predict the reaction conditions considering different variables. The chemical analysis of protein hydrolysate showed high protein content (83.78%) and low fat content (0.34%). CONCLUSION: Our results showed that protein hydrolysate of sheep visceral, can be used as a natural antioxidant with high nutritional value.