Pistacia terebinthus Resin as Yeast Immobilization Support for Alcoholic Fermentation

Advancing Pistacia terebinthus L. (Anacardiaceae) Research: Food Preservation, Functional Foods, and Nutraceutical Potential

Pistacia terebinthus L., commonly known as the turpentine tree, is a wild-growing species with a well-documented history of use in traditional medicine and ethnobotany. Various parts of the plant-fruits, seeds, resin, leaves, and galls-have demonstrated significant bioactive potential, particularly antioxidant, antimicrobial, and functional properties. Despite these promising attributes, the industrial application of P. terebinthus L. in contemporary food and nutraceutical systems remains limited and underexplored. Recent advances have employed a range of technological strategies-including encapsulation, active food packaging, emulsion stabilization, probiotic immobilization, and fermentation-to improve the stability, bioavailability, and functional performance of P. terebinthus L.-derived extracts within food matrices. These approaches have shown potential in enhancing aroma retention, extending shelf life, and supporting probiotic viability, thereby positioning P. terebinthus L. as a promising candidate for use in functional formulations and natural food preservation. Nevertheless, further investigation is required to optimize processing parameters, assess the long-term stability of bioactive compounds, and establish standardized regulatory frameworks. Addressing these challenges will be essential for facilitating the broader integration of P. terebinthus L. into the functional food, nutraceutical, and food preservation industries.

The microsphere of sodium alginate-chitosan-Pichia kudriavzevii enhanced esterase activity to increase the content of esters in Baijiu solid-state fermentation

Pichia kudriavzevii was one of the important aroma-producing fungi in the solid-state fermentation of Baijiu, and immobilization was an effective strategy for improving microbial performance. Herein, P. kudriavzevii cells were immobilized in a gel network that crosslinked by chitosan and sodium alginate to form sodium alginate/chitosan-P. kudriavzevii microspheres (SA/CS-PMs). Their structural characteristics and formation processes were characterized by SEM and FT-IR. The effect of synthesis conditions on the performance of microspheres were determined by single-factor experiments. Under the optimal conditions, the SA/CS-PMs could increase the amylase activity of the fermentation broth by 57.18%, the esterase activity by 66.13%, the content of ester by 67.04%, and could be reused at least three times. Further research results indicated that the content of ester could be increased significantly in Baijiu solid-state fermentation with the SA/CS-PMs. In conclusion, the SA/CS-PMs could improve the ester production ability of P. kudriavzevii by increasing the esterase activity, which was a valuable exploration of directional biosynthesis and a feasible strategy to improve solid-state fermentation quality.

Application of natural and synthetic zeolites in the oenological field

Zeolites are crystalline hydrated aluminosilicates, of natural or synthetic origin, characterized by a microporous structure and high adsorption properties. They are employed as soil amendments and fertilizer carriers in agriculture, as catalysts, detergents, adsorbents and molecular sieves in many chemical processes, as well as in water and soil decontamination, and in food processing. They have been also tested in the oenological field for several potential applications; yet an overview on such topic is not still available. The present review summarizes the recent and innovative applications of zeolites in winemaking and supplies a critical discussion about their potential to prevent protein haze, tartrate instability or the appearance of certain defects, like light-struck off-flavour and earthy off-flavours. Further applications of these minerals in the management of winery wastes and in the analytical field are also reviewed. The outcomes of this work evidenced the need of further research on the use of zeolites in oenology for better exploiting their peculiar sorption and exchange properties, selecting the most efficient natural types and improving the performances of the synthetic ones, without disregarding the potential secondary effects of these treatments on wine quality.

Refining Citrus Wastes: From Discarded Oranges to Efficient Brewing Biocatalyst, Aromatic Beer, and Alternative Yeast Extract Production

Agro-industrial wastes can be valorized as biorefinery raw materials through innovative, environmentally friendly bioprocessing for added value products. In this study, a process for citrus waste valorization within the biorefinery concept is proposed, including the development of an effective biocatalyst, based on immobilized cells, for aromatic beer production, and an alternative yeast extract (AYE) production in the same unit. Specifically, orange pulp from discarded oranges was applied as an immobilization carrier of the alcohol-resistant and cryotolerant yeast strain S. cerevisiae AXAZ-1. The yeast culture was produced by minor nutrient supplementation using diluted molasses as substrate. An effective Citrus Waste Brewing Biocatalyst (CWBB) was produced and applied for beer fermentation. The aroma-related compounds in beer produced with free yeast cells or the CWBB were evaluated by solid-phase micro-extraction (SPME) gas chromatography–mass spectrometry (GC–MS). The analysis showed that the beers produced by the CWBB had a more complex volatile profile compared with beer fermented by the free cells. More specifically, the CWBB enhanced the formation of esters and terpenes by 5- and 27-fold, respectively. In the frame of the proposed multiprocessing biorefinery concept, the spent CWBB, after it has completed its cycle of brewing batches, was used as substrate for AYE production through autolysis. The produced AYE significantly affected the yeast growth when compared to commercial yeast extract (CYE). More specifically, it promoted the biomass productivity and biomass yield factor by 60–150% and 110–170%, respectively. Thus, AYE could be successfully used for industrial cell growth as an efficient and cheaper substitute of CYE. Within a circular economy framework, the present study highlights the potential use of citrus waste to produce aromatic beer combined with AYE production as an alternative way to valorize these wastes.

Entrapped Psychrotolerant Yeast Cells within Pine Sawdust for Low Temperature Wine Making: Impact on Wine Quality

An alternative methodology is proposed for low temperature winemaking using freeze-dried raw materials. Pine sawdust was delignified and the received porous cellulosic material was applied as immobilization carrier of the psychrotolerant yeast strain Saccharomyces cerevisiae AXAZ-1. The immobilization of yeast cells was examined and verified by scanning electron microscopy (SEM). The immobilized biocatalyst and high-gravity grape must were separately freeze-dried without cryoprotectants and stored at room temperature (20–22 °C) for 3 months. The effect of storage on the fermentation efficiency of the immobilized biocatalyst at low temperatures (1–10 °C), as well as on the aromatic characteristics of the produced wines was evaluated. Storage time had no significant effect on the fermentation efficiency of the biocatalyst resulting in most cases in high ethanol production 13.8–14.8% v/v. The volatile fraction of the produced wines was examined using headspace solid-phase microextraction (HS-SPME) followed by gas chromatography mass spectrometry (GC/MS). GC-MS/SPME analysis along with the organoleptic evaluation revealed in all produced wines a plethora of fresh and fruit aromatic notes. To conclude, fermentation kinetics and aromatic profile evaluation encourages the production of high-quality sweet wines at low temperatures using pine sawdust (Pinus halepensis) entrapped yeast cells as a promoter.

Enhanced Aromatic Profile and Functionality of Cheese Whey Beverages by Incorporation of Probiotic Cells Immobilized on Pistacia terebinthus Resin

: In the present study, cheese whey was utilized for the development of a novel functional beverage, using Lactobacillus casei ATCC 393 probiotic cells immobilized on Pistacia terebinthus resin (pissa Paphos). Evaluation of shelf life of the produced beverages showed that spoilage microorganisms were not observed in beverages containing P. terebinthus resin. Terpenes' rich content might have contributed to the antimicrobial activity of the produced beverages; however, no significant effect on the viability of the immobilized probiotic cells was obtained. Whey beverages containing the immobilized biocatalyst retained a high viability (>1 × 106 CFU/g) of probiotic cells during a storage period of 30 days at 4 °C. The superiority of whey beverages containing the immobilized biocatalyst was also highlighted by GC-MS analysis, while the enhanced aromatic profile, which was mostly attributed to the higher concentration of terpenes, was also detected during the sensory evaluation performed. Conclusively, this study indicated the high commercialization potential of these novel functional whey beverages, within the frame of a sustainable dairy waste valorization approach. To the best of our knowledge, this is the first food-oriented approach within the guidelines of the circular economy reported in the literature, using the autochthonous Pistacia terebinthus resin for the production of functional whey beverages.