Volatile compounds of a pumpkin (Cucurbita moschata) purée processed by high pressure thermal processing

Techno-functional properties and enhanced consumer acceptance of whipped fermented milk with Ficus carica L. By-products

The development of new fermented milks formulations enriched with fruit by-products may widen the existing market offer of products matching consumer demands on novel, and "no artificial added sugars" products. Unmarketable fig fruit, food by-product, could be considered as a potential ingredient to develop a new dairy product. The aim of this study was to study the consumer acceptance of fermented milk enriched with different percentage of pasteurized fig purée (by-products) and their technological properties. It was found that the quantity of fig puree added influenced fermented milks texture and spontaneous syneresis. Formulations containing 40% fig puree showed the highest values of firmness, consistency, cohesiveness, and viscosity index with improvements seen from 20% fig puree addition. Furthermore, the inclusion of fig puree in fermented milks reduced the levels of lactic acid bacteria comparing with control samples, but the microbial load was higher than 106 UFC g-1 LAB (estimated counts in MRS) and 9 UFC g-1 LAC (estimated counts in M17). Polyphenolic content increased with fig puree percentage, enhancing antioxidant activity. Volatile compound analysis identified hexanoic acid, acetoin, and butanoic acid as predominant in enriched fermented milks. It is also worth highlighting that sensory evaluation revealed better ratings for texture and sweetness acceptance in formulations containing 30% and 40% of fig puree, correlating with instrumental data. Overall, the quality parameters were maintained and even improved, leading to high consumer acceptability ratings.

Assessment of the ‘taro-like’ aroma of pumpkin fruit (Cucurbita moschata D.) via E-nose, GC–MS and GC-O analysis

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E-nose and GC–MS could distinguish the different pumpkin based on aroma profiles and volatile compounds.

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It’s the first time to study the key volatile compound associated with ‘taro-like’ aroma of pumpkin fruit.

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2-Acetyl-1-pyrroline is the key contributor to the ‘taro-like’ aroma of pumpkin fruit.

‘Taro-like’ aroma is a pleasant flavor and value-added trait in pumpkin species imparted by unknown key volatile compounds. In this study, we used the electronic nose (E-nose), gas chromatography-mass spectrometry (GC–MS), and GC-Olfactometry (GC-O) to study the aroma profile, volatile compounds, and key contributors, respectively. By E-nose and GC–MS, we found significant differences in the aroma profiles and volatile compounds between fruits from five samples with/without ‘taro-like’ aroma. According to the analysis of differential volatile compounds obtained from GC–MS and the GC-O analysis of the sample with ‘taro-like’ aroma, we found that 2-acetyl-1-pyrroline representing the ‘taro’ odor was only identified in the sample with ‘taro-like’ aroma. Therefore, we conclude that 2-acetyl-1-pyrroline is the key contributor to the 'taro-like' aroma. Moreover, the relationship between 2-acetyl-1-pyrroline and ‘taro-like’ aroma was further verified via other pumpkin samples. Our results provide a theoretical basis for understanding the aroma characteristics of pumpkin fruit.

Characterization of Volatile Organic Compounds in Kiwiberries (Actinidia arguta) Exposed to High Hydrostatic Pressure Processing by HS-SPME/GC-MS

HS-SPME/GC-MS analysis was carried out to characterize the profile of volatile organic compounds (VOCs) in kiwiberry cultivars (Geneva and Weiki) exposed to high hydrostatic pressure (HHP) (450–550–650/5 and 15 min). The sum of individual VOCs in Geneva (6.493 mg/kg) and Weiki (11.939 mg/kg) samples was found to be significantly reduced after processing, particularly for pressurization conditions of 650 MPa/15 min (decrease of 62%) and 550 MPa/15 min (decrease of 84%), respectively. On the other hand, Geneva and Weiki exposed to 450 MPa/5 min manifested the lowest loss in the sum of the VOCs. Geneva exposure to 450 MPa/5 min led to an increase in the hexanal (r = 0.782) and linalool (r = 0.806) content. Sample pressurization (450 MPa/15 min) promoted the formation of methyl butanoate, ethyl hexanoate, and cis-geraniol, simultaneously increasing the benzaldehyde (r = 0.886) concentration. However, the treatment of Weiki at 450 MPa/5 min favored trans-2-heptenal (r = 0.999) and linalool (r = 0.970) formation, as well as the (-)-terpinen-4-ol (r = 0.848) and geraniol (r = 0.694) content. Ethyl butanoate, hexanal, and 1-octen-3-ol were highly concentrated in the HHP-treated (450 MPa/5 or 15 min) Weiki. Pressurization decreased the terpenoid contribution, but also increased the contribution of alcohols and aldehydes to the overall VOC number in both tested cultivars.

Effects of High Hydrostatic Pressure Combined with Vacuum-Freeze Drying on the Aroma-Active Compounds in Blended Pumpkin, Mango, and Jujube Juice

A combination process of completely non-thermal processing methods involving high hydrostatic pressure (HHP) and vacuum-freeze drying (VFD) for producing a new snack from fruit and vegetable blends was developed, and the effect of the process on flavor quality was investigated. The HHP-VFD treatment did not significantly reduce volatile compound contents compared to single HHP or VFD. Gas chromatography-olfactometry showed that HHP-VFD raised the contents of floral-like volatile compounds (e.g., β-ionone) compared to the untreated sample. Sensory evaluation analysis confirmed that the overall liking was unchanged after the HHP-VFD treatment. The HHP-VFD combined treatment is effective in maintaining the flavor and extending shelf life, and is convenient for the portability and transportation of ready-to-drink juice.