Physicochemical properties of apple juice during sequential steps of the industrial processing and functional properties of pectin fractions from the generated pomace

The potential of red-fleshed apples for cider production

Cider quality is influenced by numerous factors relating to the apples used during production. While extensive research has been done to explore the phenolic content, sensory quality, and storage stability of various apple products, the domain of fermented apple products, such as ciders, remains underrepresented. Red-fleshed apples (RFAs) have naturally high concentrations of phenolic compounds, which indicate their potential in the production of novel cider products. However, a knowledge gap remains regarding the application of RFAs in cider production and how their physicochemical and sensory properties are changed during processing. This review is the first to comprehensively investigate whether and to what extent apple categories (dessert, cider, and RFAs) differ regarding their physicochemical and sensory properties from harvest throughout cider processing. Furthermore, it highlights the importance of a holistic understanding of apple characteristics, encompassing both traditional and RFA varieties in the context of cider production. The findings offer valuable insights for stakeholders aiming to enhance product quality, providing a foundation for future studies on optimizing processing methods for a diverse and appealing range of ciders.

Fruit residues as biomass for bioethanol production using enzymatic hydrolysis as pretreatment

The commercialization of fruits in markets generates a large amount of waste because they are perishable and have a short shelf life, so, they are discarded. This study aimed to provide a noble end to discarded fruits that have fermentable sugars. Banana, apple, mango and papaya residues were collected from supermarkets and underwent an enzymatic hydrolysis process. The ability of four pectinases, two amylases, one xylanase and one cellulase to release reducing sugars from fruit biomass before fermentation with two yeast strains (S. cerevisiae CAT-1 and S. cerevisiae Angel) for bioethanol production was investigated, obtaining a total of RS (Reducing sugar) of 268.08 mg/mL in banana residues. A fermentation with yeast S. cerevisiae CAT-1 resulted in 98% consumption of RS and the production of a total of 28.02 g/L of ethanol. Furthermore, fermentation with the yeast S. cerevisiae Angel, resulted in 97% RS consumption and 31.87 g/L ethanol production, which was the best result obtained throughout all the tests of hydrolysis, highlighting the banana residue as a promising biomass for the production of bioethanol.

Metabolomic analysis and physical attributes of ripe fruits from Mexican Creole (Persea americana var. Drymifolia) and 'Hass' avocados

The physicochemical properties, including nutrient and bioactive compound compositions, in fruit of four creole avocados (CA) from Mexico were determined and compared with those of 'Hass' fruit. 'Hass' pulp and some CA pulps contained similar concentrations of lutein, chlorophyll a, β-sitosterol and α-tocopherol. CA pulp contained 3.91-9.55% more oil than 'Hass'. Oil from CA pulp contained 10.10-26.79% more oleic acid than 'Hass' pulp. However, CA were small (CA = 81.40-137.15 g, 'Hass' = 188.59 g) and their pulp contents were low (CA = 39.83-84.82 g, 'Hass' = 144.14 g). CA peels were very thin, making these avocado peels edible but prone to mechanical damage. CA peels also contained higher concentrations and greater diversity of anthocyanins and glycosylated quercetin compounds than 'Hass' peels. Some CA were particularly rich in mannoheptulose and perseitol. Consumption of CA, including their peel, might result in higher intakes of some nutrients and bioactive compounds compared with 'Hass' avocados.

An Overview of the Factors Influencing Apple Cider Sensory and Microbial Quality from Raw Materials to Emerging Processing Technologies

Given apple, an easily adapted culture, and a large number of apple varieties, the production of apple cider is widespread globally. Through the fermentation process, a series of chemical changes take place depending on the apple juice composition, type of microorganism involved and technology applied. Following both fermentations, alcoholic and malo-lactic, and during maturation, the sensory profile of cider changes. This review summarises the current knowledge about the influence of apple variety and microorganisms involved in cider fermentation on the sensory and volatile profiles of cider. Implications of both Saccharomyces, non-Saccharomyces yeast and lactic acid bacteria, respectively, are discussed. Also are presented the emerging technologies applied to cider processing (pulsed electric field, microwave extraction, enzymatic, ultraviolet and ultrasound treatments, high-pressure and pulsed light processing) and the latest trends for a balanced production in terms of sustainability, authenticity and consumer preferences.

Effect of cultivar on the content of selected phytochemicals in avocado peels

The peels of ripe fruit of 'Hass' and 'Hass' type (HT) avocado cultivars were evaluated for phytochemical composition and other attributes. Peels represented from 8.78 to 14.11% of fruit weight. Their color ranged from homogeneous black to black with very small greenish spots. The oil content in the peels was low. Twelve fatty acids were identified in peel oil and the ratio of unsaturated to saturated fatty acids suggested that peel oil might contribute to human health. The phytochemical composition varied significantly with cultivar. However, many HT peels were superior than 'Hass' peel in their content of α-tocopherol, β-sitosterol, perseitol, and cyanidin-3-glucoside, which was up to 211.67, 45.92, 337.17, and 519.27% higher in HT peels, respectively. The content of some phenolic compounds, especially procyanidin B2 and epicatechin, was significantly lower in 'Hass' than in many HT peels. Few HT peels showed a higher content of carotenoids and chlorophyll than 'Hass' peels. Lutein was the most abundant carotenoid. Chlorophyll a and b were also abundant in peels and low concentrations of chlorophyll derivatives were observed. Avocado peels are an important source of bioactive compounds, including some carotenoids, acids, sterols, and volemitol, which were observed for the first time.

Rheological characterization of RG-I chicory root pectin extracted by hot alkali and chelators

This work aimed to extract gelatinous chicory root pectin (CRP) and evaluated the rheological behavior of the dispersions and gels. CRP was extracted by citric acid (CEP), alkaline (AEP), ammonium oxalate (OEP) and sodium citrate (SEP). The yield, molecular weight (Mw) and the degree of esterification (DE) of pectin samples varied from 8.8 to 14.8% (w/w), 204 to 336 k Da and 4.0 to 47.4%, respectively. AFM studies showed self-organize on mica of CEP, revealing a random coil conformation due to the interaction of multiple branching, whereas, AEP exhibited long linear filamentous structures. The flow behavior study verified the pseudoplastic character of CEP and SEP at 25 °C, while OEP and AEP belonged to dilatant fluid, besides, a closed hysteresis loop was observed when the CEP concentration increased to 1.5%. OEP gel was thermo insensitive and stiff, AEP gel presented most sensitive to calcium ion but more brittle, and SEP was observed a weak syneresis in spite of the poor gelation property. The texture analysis indicated OEP gel had a superior firmness and chewiness. These findings demonstrated that CRP may be attractive as a thickener or gelling agent to modulate textures of sugar-free and calcium content food.

Structure-Related Gelling of Pectins and Linking with Other Natural Compounds: A Review

Pectins are polysaccharides present commonly in dicotyledonous and non-grass monocotyledonous plants. Depending on the source, pectins may vary in molecular size, degrees of acetylation and methylation and contents of galacturonic acid and neutral sugar residues. Therefore, pectins demonstrate versatile gelling properties and are capable of forming complexes with other natural compounds, and as a result, they are useful for designing food products. This review focuses on the structure-related mechanisms of pectin gelling and linking with other natural compounds such as cellulose, hemicellulose, ferulic acid, proteins, starch, and chitosan. For each system, optimal conditions for obtaining useful functionality for food design are described. This review strongly recommends that pectins, as a natural biocomponent, should be the focus for both the food industry and the bioeconomy since pectins are abundant in fruits and may also be extracted from cell walls in a similar way to cellulose and hemicellulose. However, due to the complexity of the pectin family and the dynamic structural changes during plant organ development, a more intensive study of their structure-related properties is necessary. Fractioning using different solvents at well-defined development stages and an in-depth study of the molecular structure and properties within each fraction and stage, is one possible way to proceed with the investigation.