Effect of Packaging and Storage Temperature on the Shelf Life of Crisps from four Kenyan Potato Cultivars

The progression of lipid oxidation, β-carotenes degradation and sensory perception of batch-fried sliced sweet potato crisps during storage

Dee are a unique and rapidly growing part of the global snack food market and are recognised as having distinct sensory properties (taste and texture). In this study, the development of important volatile aroma compounds over storage was evaluated and their chemical origin explained. Sweet potatoes were batch fried in high oleic sunflower oil (HOSO) and subjected to accelerated shelf life testing. Headspace volatiles were analysed using SPME GC-MS and correlated with sensory perception. All the components (sweet potatoes, oil and β-carotene) showed significant degradation after 3 weeks of storage at accelerated conditions (equivalent to 12 weeks in real-time at 25 °C). Marker volatiles associated with lipid oxidation such as hexanal, octanal, pentanal were identified, in addition to norisoprenoids from β-carotene degradation such as β-ionon, 5,6-epoxy-β-ionone, dihydroactinidiolide (DHA) and β-cyclocitral. The most prominent marker of lipid oxidation (hexanal) rapidly increased at week 1, whereas the carotene degradation makers did not rapidly increase until week 3 suggesting a delayed response. The frying temperature during the batch frying process of SPC was also shown to play a significant role in the sensory perception of the product over the shelf life. Overall, the results suggest that tight control of process variables and raw material design may enable extended shelf life and potentially enhanced health credentials for the product. These findings are unique to SPC, but also of value to the wider food industry.

Lipid oxidation markers, degradation markers of β-carotene and changes in sensory properties were tracked in fried sliced sweet potatoes over shelf life and under different frying conditions.

Lyophilized Probiotic Lactic Acid Bacteria Viability in Potato Chips and Its Impact on Oil Oxidation

To produce a new probiotic-containing food product, potato chips, as the most preferred fast food, were chosen. Preferably, it should be preserved for a long period without oxidation. The presented study aimed to compare potato chips containing two lyophilized probiotic lactic acid bacteria (Bifidobacterium longum ATCC 15708 and Lactobacillus helveticus LH-B02) in order to retard lipid oxidation. Lyophilization of probiotics was carried out into two cryoprotective media-skim milk (SM) and gelatin/glycerol (GG) as lactose-free medium. Results revealed that GG and SM media were the most suitable for lyophilization of B. longum and L. helveticus, respectively. . The lyophilized live cells were incorporated in potato chips, packed and their effect on oil oxidation was assessed. . Results showed that the lyophilized B. longum in SM remained alive at 6.5 log CFU/g for 4 months at 30 °C. Interestingly, potato chip bags containing B. longum lyophilized in SM medium exhibited a decrease in peroxide value (PV) and acid value (AV) of the extracted oil by 40.13% and 25%, respectively, compared to the control bags. The created probiotic potato chips containing B. longum fulfill the criteria of the probiotic product besides the prime quality and sensory attributes.

The impact of nitrogen gas flushing on the stability of seasonings: volatile compounds and sensory perception of cheese & onion seasoned potato crisps

The impact of natural cheese and onion seasoning on the sensory perception and shelf life stability of potato crisps was studied. This study was carried out to evaluate the impact of nitrogen (N2) gas flushing on the shelf-life stability and sensory attributes of cheese & onion seasoned potato crisps. Markers of lipid oxidation and flavour volatile compounds were evaluated in sliced, unwashed, batch fried potato crisps during accelerated storage at 45 °C for 10 weeks. Volatile flavour compounds were evaluated by headspace gas analysis using solid phase microextraction (SPME) GC-MS and correlated with sensory perception. Gas flushing significantly increases the shelf life of both unsalted and cheese & onion seasoned potato crisps in terms of the stability of volatile compounds and sensory perception. Further to this, the addition of the cheese & onion seasoning increased the shelf life of the base potato crisp; this is proposed to be explained by the antioxidant properties of milk proteins in the seasoning. Sensory evaluation indicated that the key negative sensory attributes reported were rancidity and stale attributes, which were correlated to the progression of lipid oxidation and loss of flavour over storage time irrespective of the packaging environment (with/without gas flushing).

Development and quality characteristics of nutritionally enhanced potato legume based wari- an Indian traditional savoury

The present study was carried out to develop waris from potato and legume blends and to analyze them for organoleptic, physicochemical, phytochemical and shelf life quality. Wari is a partially fermented legume based savoury, used as adjunct in vegetable curries. In this study, potato (boiled and dehydrated) was used to supplement black gram or urad dhal waris. Two processing cultivars (Kufri Chipsona-1, Kufri Chandramukhi) and one commonly grown cultivar (Kufri Pukhraj) were evaluated for processing into waris. Based on preliminary sensory trails, waris with potato (70 %) and urad dhal (30 %) level of supplementation were found to be most acceptable and these waris were subjected to nutritional evaluation. Storage stability of the waris was assessed by storing the product at room temperature for a period of 12 months. Results were compared with dhal waris (control). Protein content was significantly higher in control waris compared to potato supplemented waris. Bioactive compounds including ascorbic acid, total phenolics and total antioxidant activity measured as DPPH radical scavenging activity increased significantly on incorporation of potato. Between the cultivars, waris enriched with Kufri Pukhraj, a table variety which is considered unfit for processing, displayed the highest phytochemical content and total antioxidant activity. Sensory evaluation indicated higher overall acceptability scores of potato enriched waris compared to control waris. Between the treatments i.e. boiled mash and dehydrated flour, waris supplemented with boiled potato mash showed a significantly higher content of phytochemicals and total antioxidant activity compared to potato flour waris. However no significant difference was observed in sensory quality of the product prepared either with fresh potato mash or potato flour. Storage studies showed that the potato waris can be stored safely for 12 months with its nutrient constituents intact.