Occurrence of Patulin and Polyphenol Profile of Croatian Traditional and Conventional Apple Cultivars during Storage

Structural Similarity, Activity, and Toxicity of Mycotoxins: Combining Insights from Unsupervised and Supervised Machine Learning Algorithms

A large number of mycotoxins and related fungal metabolites have not been assessed in terms of their toxicological impacts. Current methodologies often prioritize specific target families, neglecting the complexity and presence of co-occurring compounds. This work addresses a fundamental question: Can we assess molecular similarity and predict the toxicity of mycotoxins in silico using a defined set of molecular descriptors? We propose a rapid nontarget screening approach for multiple classes of mycotoxins, integrating both unsupervised and supervised machine learning models, alongside molecular and physicochemical descriptors to enhance the understanding of structural similarity, activity, and toxicity. Clustering analyses identify natural clusters corresponding to the known mycotoxin families, indicating that mycotoxins belonging to the same cluster share similar molecular properties. However, topological descriptors play a significant role in distinguishing between acutely toxic and nonacutely toxic compounds. Random forest (RF) and neural networks (NN), combined with molecular descriptors, contribute to improved knowledge and predictive capability regarding mycotoxin toxicity profiles. RF allows the prediction of toxicity using data reflecting mainly structural features and performs well in the presence of descriptors reflecting biological activity. NN models prove to be more sensitive to biological activity descriptors than RF. The use of descriptors encompassing structural complexity and diversity, chirality and symmetry, connectivity, atomic charge, and polarizability, together with descriptors representing lipophilicity, absorption, and permeation of molecules, is crucial for predicting toxicity, facilitating broader toxicological evaluations.

Unveiling Apple Diversity: The Quality of Juice Produced from Old vs. Commercial Apple Cultivars

This research is focused on comparing the compositions of juice produced from old and commercially grown apple cultivars. We examined factors such as pH, total acids, soluble dry matter, polyphenol profile, and antioxidant activity, which impact the attributes, safety, shelf life, and nutritional value of the juice. Our analysis revealed differences between these two groups of cultivars. For instance, pH values ranged from 3.04 (in 'Bobovec') to 3.69 (in 'Fuji'). The proportions of acids varied from 0.07 g/100 mL (in 'Fuji') to 0.19 g/100 mL (in 'Wagener'). Soluble dry matter content ranged from 14.10% (in 'Fuji') to 18.50% (in 'Kraljevčica'). We also observed variations in sugar content and composition among cultivars; for example, sucrose levels varied from 16.11 g/L ('Fuji') to 39.36 g/L ('Golden Delicious). Glucose levels ranged from 4.95 g/L ('Jonagold') to 19.18 g/L ('Fuji'), while fructose levels spanned from 50.78 g/L ('Austrougarka') to 427.97 g/L ('Ilzer Rosenapfel'). Furthermore, old apple cultivars exhibited higher concentrations of phenols and flavonoids compared to commercial ones; we also noted significant variations in flavonol levels among different cultivars. The 'Wagener' and 'Božićnica' apple varieties had levels of myricetin measuring 0.53 and 0.52 µg/mL, respectively. On the other hand, 'Bobovec' stood out for its content of procyanidin B2 with a concentration of 422.61 µg/mL. When examining non-flavonoid compounds, it was found that old apple cultivars had higher concentrations of gallic acid, trans-ferulic acid, and chlorogenic acid. However, commercial cultivars showed dominance in caffeic and p-coumaric. Comparisons of antioxidant capacity using DPPH and ABTS assays clearly demonstrated the superiority of old apple cultivars. Overall, this study highlights the importance of utilizing apple cultivars for juice production. Their distinct compositions and higher antioxidant capacities contribute to potential health benefits. Preserving these cultivars for enhanced juice quality and nutritional value is encouraged. Further research could explore cultivation practices' impact on composition and health benefits.

Distribution and Stability of Polyphenols in Juices Made from Traditional Apple Cultivars Grown in Bosnia and Herzegovina

The present research was undertaken to investigate polyphenolic profiles of peel, pulp and juices made from two standard commercial and five traditional apple cultivars from Bosnia and Herzegovina. The main goal of the study was to monitor the distribution and changes of polyphenolic profiles through different phases of apples' processing into cloudy and clear juices, with regard to L-ascorbic acid pretreatment. Quantitative determination of phenolic compounds was carried out by using high-performance liquid chromatography with diode-array detection. The obtained results showed that traditional cultivars, namely 'Paradija' and 'Prijedorska zelenika', displayed significantly higher content of these compounds compared to commercial ones. Flavan 3-ols and flavonol glycosides were mostly found in peels of all cultivars (21.2-44.1 and 5.40-33.3%, respectively), while phenolic acids along with flavan 3-ols were predominant in the pulp (8.20-30.8 and 5.10-13.9%, respectively). Apples' processing into juices caused decrease (more than 90%) in the content of all polyphenols and the distribution of these compounds from fruits to final products had a negative trend, particularly evident in clear juices. The most drastic loss occurred in the flavonol glycosides and dihydrochalcones content, while chlorogenic acid displayed quite stable distribution from apples to final products due to its good solubility. Apple mash pretreatment with L-ascorbic acid had a positive impact on the preservation and retention of polyphenols.

Identification and Quantification of Polyphenols in Croatian Traditional Apple Varieties

Apples and apple-based products are particularly interesting due to being a good source of polyphenols in an everyday diet. Recently there has been increased interest in the preservation of traditional apple varieties due to studies that suggest that traditional apple varieties have a higher content of polyphenols and antioxidant activity compared to commercial varieties. This study shows that traditional apple varieties contain higher concentration of polyphenolic compounds than conventional ones, such as chlorogenic acid (1.29-456 mg/kg dw), catechin (0.70-312 mg/kg dw), epicatechin (1.75-244 mg/kg dw), procyanidin B1 + B2 (4.08-358 mg/kg dw) and quercetin-3-glucoside (0.96-231 mg/kg dw). This research underlies the great potential of traditional apple varieties as a source of natural antioxidants and polyphenolics.