The limited stability of Saccharomyces boulardii and sensitive phycobiliproteins during frozen storage, together with the growing demand for natural antioxidant ingredients, represents a challenge for developing functional probiotic ice cream. This study aimed to evaluate whether chitosan encapsulation of phycocyanin (PC) and phycoerythrin (PE) could improve pigment stability and probiotic survival while maintaining the physicochemical, antioxidant, color, textural, and sensory quality of ice cream during 8 weeks of frozen storage. PC and PE were encapsulated using 2% (w/v) chitosan and ionic gelation, followed by lyophilization. FTIR spectroscopy (4000–400 cm−1, ATR mode) was used to identify and compare functional group changes in control (C) and S. boulardii-inoculated coated-pigment (T2) ice cream samples. The coated pigments showed a particle size of 149.8 nm, zeta potential of +66.5 mV, and encapsulation efficiency of 83.37%. Among the five formulations, T2, containing S. boulardii inoculated before aging with chitosan-coated PC + PE, showed the most favorable performance. At week 8, T2 exhibited the highest total phenolic content (143 mg GAE g−1 DW vs. 86.8 mg GAE g−1 DW in the control), the lowest color change (ΔE = 6.32 vs. 12.67; ~50% reduction), and the highest probiotic viability (8.08 log CFU g−1). T2 also showed approximately 12% lower melting rate than the control, while maintaining acceptable sensory properties. FTIR showed T4 differs from the control mainly through two new bands (1701.9 cm−1, C=O; 1622.7 cm−1, CC), confirming pigment retention, plus an OH shift linked to S. boulardii activity, while the core lipid/carbohydrate matrix stayed unchanged. These findings indicate that chitosan-encapsulated PC + PE with pre-aging probiotic inoculation improves bioactive stability, probiotic survival, antioxidant capacity, and color stability, supporting its potential for functional probiotic ice cream.
This study presents a non-destructive method for assessing changes in strawberry hardness induced by pulsed electric field (PEF) treatment using optical coherence tomography (OCT). Strawberry samples were subjected to PEF at field strengths ranging from 0.3 to 1.5 kV/cm, and structural changes were evaluated using both mechanical hardness tests and OCT-based image analysis of subsurface tissue layers. Texture descriptors, including Haralick features and lacunarity measures, were extracted from OCT images to characterize microstructural heterogeneity. Due to high feature redundancy, principal component analysis (PCA) was applied, preserving over 99.7% of data variance in the textural feature space. A linear prediction model supported by RANSAC regression was developed to estimate hardness from PCA-transformed features, ensuring robustness to outliers. Model evaluation showed moderate predictive performance (mean R2 ≈ 0.6), with variability across data splits indicating sensitivity to sample heterogeneity. SHAP analysis revealed that the first principal component dominates the prediction. An additional linear regression model of changes in strawberry hardness under the influence of PEF with 7 different intensities was also introduced. Statistical analysis confirmed a significant effect of PEF on hardness (p = 0.002, η2=0.365). The results show that OCT combined with machine learning shows promising potential for exploring the non-invasive monitoring of PEF-induced structural changes associated with fruit tissue hardness.
Cold plasma (CP) technology has emerged as a promising non-thermal processing approach for improving the safety, quality, and shelf life of plant-based foods. Unlike conventional thermal treatments, CP operates at near-ambient temperatures, enabling effective microbial decontamination while preserving sensory and nutritional attributes. The technology generates reactive oxygen and nitrogen species (RONS), ultraviolet photons, ions, and charged particles that collectively contribute to microbial inactivation through oxidative damage to cell membranes, proteins, and nucleic acids. Various CP systems, including dielectric barrier discharge (DBD), atmospheric pressure plasma jet (APPJ), corona discharge, and plasma-activated water (PAW), have demonstrated effectiveness against bacteria, fungi, spores, biofilms, and viruses in fruits, vegetables, cereals, spices, and plant-derived products. The efficacy of CP is strongly influenced by process parameters such as voltage, treatment duration, gas composition, humidity, and reactor design, as well as by plant surface characteristics and food matrix composition. Beyond microbial control, CP can modify carbohydrates, proteins, lipids, vitamins, and bioactive compounds, potentially enhancing functional properties and extraction efficiency while maintaining product quality. However, excessive exposure may lead to oxidative degradation, pigment loss, nutrient deterioration, and the formation of undesirable compounds such as lipid oxidation products and nitrosamines. Plasma-activated water has also gained attention as an indirect sanitization strategy for washing and minimally processed foods. Despite its considerable potential, challenges related to process standardization, industrial scalability, regulatory approval, and long-term safety assessment remain unresolved. Overall, CP represents a sustainable and innovative technology for next-generation food processing and preservation of plant-based foods.
Food waste is a major challenge for the global food system, with approximately one-third of all food produced for human consumption lost or wasted annually. A large portion of this waste occurs due to post-harvest spoilage of perishable products such as fruits, confectionery products, and processed foods. Freezing technologies are widely used to extend shelf life and preserve food quality by inhibiting microbial growth and slowing biochemical reactions. However, conventional freezing methods often cause structural damage due to ice crystal formation, resulting in quality loss and potential food waste. In recent years, innovative freezing techniques such as acoustic extra freezing (AEF) and ultrasound-assisted freezing (UAF) have been investigated to improve freezing efficiency and preserve food microstructure. This mini-review summarizes the current state of research on freezing technologies for fruits and chocolate, including industrial shock freezing, household freezing, and emerging assisted freezing techniques. Particular attention is given to the mechanisms, advantages, and limitations of AEF and UAF systems, as well as their potential role in reducing food waste within the food supply chain. Particular attention is given to the mechanisms, advantages, and limitations of AEF and UAF systems, as well as their potential role in reducing food waste within the food supply chain. Overall, the available evidence indicates that UAF is currently supported by a substantially stronger body of scientific literature and demonstrates consistent improvements in freezing performance and product quality, whereas AEF remains a promising but still emerging technology whose mechanisms and practical applicability require further experimental validation.
