Effect of high-pressure processing on immunoreactivity, microbial and physicochemical properties of hazelnut milk

Impact of high-pressure processing on rheological, dispersive, and sensorial quality attributes of oat milk

Oat milk has attracted considerable consumer interest because of its high nutritional value, dietary fiber content, and phytochemical content. High-pressure processing (HPP) increases the shelf life of food while maintaining its nutritional value. However, HPP is known to induce rheological changes. Therefore, this study aimed to assess the rheological and microbiological characteristics of oat milk and the effect of HPP on various pressure levels. Oat milk was prepared and then treated with high-pressure processing (300-600 MPa) and heat. Subsequently, it was evaluated for its rheological properties, color, microbial content, and sensory attributes. Oat milk processed at 600 MPa was found to have improved viscosity (0.015-0.99, Pa.s), color, protein content, and homogenization compared to other treatments (p ≤ 0.05). The HPP inactivated mesophilic and psychotropic microorganisms, resulting in a 5-log drop in total microbial counts at 600 MPa. The panelists perceived that the sensory characteristics of the sample treated at 600 MPa were similar to those of samples that had been heat-treated (p < 0.05). High-pressure processing at 600 MPa effectively inhibited vegetative cells without negatively impacting the rheological properties of oat milk, in contrast to heat-treated milk.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-024-06040-x.

Novel cold and thermally pasteurized cardoon-enriched functional smoothie formulations: A zero-waste manufacturing approach

This study investigated the potential of incorporating cardoon (Cynara cardunculus L.) blades as bioactive and dietary fiber ingredients in vegetable/fruit-based smoothies, within a zero-waste approach. The smoothie formulations were pasteurized by high-pressure (550 MPa for 3 min, HPP) and thermal (90 °C for 30 s, TP) treatments and stored at 4 °C for 50 days. Cardoon-fortified smoothies exhibited higher viscosity, darker color, increased phenolic compound levels, and greater anti-inflammatory and antioxidant activities. Furthermore, the cardoon blade ingredients contributed to a more stable dietary fiber content throughout the smoothies' shelf-life. HPP-processed smoothies did not contain sucrose, suggesting enzymatic activity that resulted in sucrose hydrolysis. All beverage formulations had low or no microbial growth within European limits. In conclusion, the fortification of smoothies with cardoon blades enhanced bioactive properties and quality attributes during their shelf-life, highlighting the potential of this plant material as a potential functional food ingredient in a circular economy context.

The role of fermentation with lactic acid bacteria in quality and health effects of plant-based dairy analogues

The modern food industry is undergoing a rapid change with the trend of production of plant-based food products that are more sustainable and have less impact on nature. Plant-based dairy analogues have been increasingly popular due to their suitability for individuals with milk protein allergy or lactose intolerance and those preferring a plant-based diet. Nevertheless, plant-based products still have insufficient nutritional quality, undesirable structure, and earthy, green, and bean-like flavor compared to dairy products. In addition, most plant-based foods contain lesser amounts of essential nutrients, antinutrients limiting the bioavailability of some nutrients, and allergenic proteins. Novel processing technologies can be applied to have a homogeneous and stable structure. On the other hand, fermentation of plant-based matrix with lactic acid bacteria can provide a solution to most of these problems. Additional nutrients can be produced and antinutrients can be degraded by bacterial metabolism, thereby increasing nutritional value. Allergenic proteins can be hydrolyzed reducing their immunoreactivity. In addition, fermentation has been found to reduce undesired flavors and to enhance various bioactivities of plant foods. However, the main challenge in the production of fermented plant-based dairy analogues is to mimic familiar dairy-like flavors by producing the major flavor compounds other than organic acids, yielding a flavor profile similar to those of fermented dairy products. Further studies are required for the improvement of the flavor of fermented plant-based dairy analogues through the selection of special microbial cultures and formulations.

Quality of bee pollen submitted to drying, pasteurization, and high-pressure processing - A comparative approach

Bee Pollen is a valuable and useful natural food product that can be used for different purposes, among which medical ones. This matrix is deemed a superfood because of its chemical composition, which is rich in nutrients and possesses significant bioactivities, including antioxidant and microbiological properties. Nevertheless, the storage conditions and processing methods must be optimized to maintain their properties and maximise their application. This work investigates the best bee pollen conservation process and its impact on individual constituents. Monofloral bee pollen was analysed for 30 and 60 days after three different storage processes (drying, pasteurization, and high-pressure pasteurization). The results showed a decrease mainly in fatty acid and amino acid content for the dried samples. The best results were obtained with high-pressure pasteurization, maintaining the proteins, amino acids and lipids characteristics of pollen and the lowest microbial contamination.

Plant-based milk: unravel the changes of the antioxidant index during processing and storage - a review

As a nutrient rich emulsion extracted from plant materials, plant-based milk (PBM) has been the latest trend and hot topic in the food industry due to the growing awareness of consumers toward plant-based products in managing the environmental (carbon footprint and land utility), ethical (animal well-fare) and societal (health-conscious) issues. There have been extensive studies and reviews done to discuss the distinct perspective of PBM including its production, health effects and market acceptance. However, not much has been emphasized on the valuable antioxidants present in PBM which is one of the attributes making them stand apart from dairy milk. The amounts of antioxidants in PBM are important. They offered tremendous health benefits in maintaining optimum health and reducing the risk of various health disorders. Therefore, enhancing the extraction of antioxidants and preserving their activity during production and storage is important. However, there is a lack of a comprehensive review of how these antioxidants changes in response to different processing steps involved in PBM production. Presumably, antioxidants in PBM could be potentially lost due to thermal degradation, oxidation or leaching into processing water. Hence, this paper aims to fill the gaps by addressing an extensive review of how different production steps (germination, roasting, soaking, blanching, grinding and filtration, and microbial inactivation) affect the antioxidant content in PBM. In addition, the effect of different microbial inactivation treatments (thermal or non-thermal processing) on the alteration of antioxidant in PBM was also highlighted. This paper can provide useful insight for the industry that aims in selecting suitable processing steps to produce PBM products that carry with them a health declaration.

Effect of sonication, microwaves and high-pressure processing on ACE-inhibitory activity and antioxidant potential of Cheddar cheese during ripening

Dairy processing provides acceptable safety and shelf-life to final products, and improves their bioactivity. The present study evaluated the potential of different milk processing techniques to improve the antioxidant and angiotensin-I converting enzyme (ACE)-inhibitory activity of Cheddar cheese, during ripening. Cheese was made from milk subjected to different pre-treatments (C = untreated control, US-1 = ultrasonication, specific energy = 23 J/g, 20 kHz frequency; US-2 = Ultrasonication specific energy = 41 J/g, 20 kHz; HPP = high-pressure processing, 400 MPa for 15 min, at temperature < 40 °C; MW = microwave, temperature<40 °C, specific energy = 86.5 J/g) and analysed after ripening for 0, 3, 6 and 9 months. The results showed that the rate of proteolysis during both cheese making and subsequent ripening was significantly affected by the pre-treatment. Antioxidant activity and ACE-inhibitory potential of cheeses made from pre-treated milk significantly increased (p < 0.05) in the following order: US-2 > HPP > US-1 > MW > C. These findings demonstrate the possibility of using ultrasound, microwaves or high-pressure processing as pre-treatments to improve the nutritional attributes of cheese.

Microbial Shelf-Life, Starch Physicochemical Properties, and in Vitro Digestibility of Pigeon Pea Milk Altered by High Pressure Processing

This study examined the effects of high-pressure processing (HPP) on microbial shelf-life, starch contents, and starch gelatinization characteristics of pigeon pea milk. HPP at 200 MPa/240 s, 400 MPa/210 s, and 600 MPa/150 s reduced the count of Escherichia coli O157:H7 in pigeon pea milk by more than 5 log CFU/mL. During the subsequent 21-day refrigerated storage period, the same level of microbial safety was achieved in both HPP-treated and high-temperature short-time (HTST)-pasteurized pigeon pea milk. Differential scanning calorimetry and scanning electron microscope revealed that HPP at 600 MPa and HTST caused a higher degree of gelatinization in pigeon pea milk, with enthalpy of gelatinization (∆H) being undetectable for both treatments. In contrast, HPP at 400 MPa led to an increase in the onset temperature, peak temperature, and conclusion temperature, and a decrease in ∆H, with gelatinization percentages only reaching 18.4%. Results of an in vitro digestibility experiment indicate that maximum resistant starch and slowly digestible starch contents as well as a decreased glycemic index were achieved with HPP at 400 MPa. These results demonstrate that HPP not only prolongs the shelf-life of pigeon pea milk but also alters the structural characteristics of starches and enhances the nutritional value.

Health issues and technological aspects of plant-based alternative milk

A growing number of consumers opt for plant-based milk substitutes for medical reasons, like cow's milk protein allergy (CMPA), lactose intolerance (LI), or as a lifestyle choice. Plant-based milk substitutes, or plant extracts, are water-soluble extracts of legumes, oilseeds, cereals or pseudocereals that resemble bovine milk in appearance. It is produced by reducing the size of the raw material, extracted in water and subsequently homogenized, being an alternative to cow's milk. They are considered cow's milk replacers due to similar chemical composition and can also be used as a substitute for direct use or in some animal milk-based preparations. On the other hand, these substitutes exhibit different sensory characteristics, stability and nutritional composition from cow's milk. They are manufactured by extracting the raw material in water, separating the liquid, and formulating the final product. Others process like homogenization and thermal treatments are indispensable to improve the suspension and microbiological stabilities of the final product so that can be consumed. However new and advanced non-thermal processing technologies such as ultra-high pressure homogenization and pulsed electric field processing are being researched for tackling the problems related to increase of shelf life, emulsion stability, nutritional completeness and sensory acceptability without the use of high temperatures. Some pre-treatments such as peeling, bleaching or soaking can be performed on the raw material in order to improve the final product. The nutritional properties are influenced by the plant source, processing, and fortification. The addition of other ingredients as sugar, oil and flavorings is done to the plant-based milk substitute to make them more palatable and be more acceptable to consumers. Thus, the aim is to review the main reasons for the consumption of plant-based milk substitute as well as the raw materials used and the technological aspects of its production.